The Demon Tech Modems FAQ

Compiled by Tez Boyes

0.1 - Contents
    0.2 - PreRamble
    0.3 - Changes
    0.4 - Why are we here?
        0.4.1 - What is the purpose of demon.tech.modems?
    0.5 - Do I have a problem?
        0.5.1 - What is the source of the problem?
        0.5.2 - Where do I report problems?
        0.5.3 - How do I report problems?
1.0 - References

2.0 - General Questions

    2.1 - What kind of modems do Demon use?
    2.2 - Do I have a problem with my modem?
    2.3 - How do I find out the ROM version of my modem?
    2.4 - How do I use a Comms/Terminal package to get this information?
    2.5 - What are all these AT commands anyway?
    2.6 - I've RTFM and I still don't understand what these AT commands
do
    2.7 - The modem always answers calls before I can!
3.0 - K56Flex, X2, 56K
    3.1 - Which versions of 56K technology are supported by Demon?
    3.2 - Which versions of 56K technology are usable with Demon?
    3.3 - Which 56K modem should I buy?
    3.4 - Where do I get a flash upgrade for my modem?
    3.5 - What is the "best" init string for my modem?
    3.6 - And what are these new AT commands?
    3.7 - Where do I report faults with the test number?
4.0 - Slow, Dropped and No Connections, Network Death, Loss of Routeing
    4.1 - I only get xxxk/s from Demon, why?
    4.2 - Overruns & Errors
    4.3 - Why did my connection drop after x mins?
    4.4 - What's "Loss of Routeing"?
    4.5 - What's Network Death?
5.0 - The Need For Speed
    5.1 - How do I tell what speed I connected to Demon at?
    5.2 - How fast should I be able to download files?
    5.3 - Why is COLT so much slower than Energis?
6.0 - Setting Init Strings and Modem Responses (32-bit Windows)
    6.1 - Why does my modem claim to connect at 115,200 bps ?
    6.2 - How do I change the modem init string in Turnpike?
    6.3 - How do I change the modem init string in Win95
    6.4 - AT&V1 gives no last connect info
    6.5 - How can I see the "CONNECT" (DTE) speed with DUN
7.0 - Misc. Stuff
    7.1 - Modems, Soundcards and Phonecalls
    7.2 - Caller ID
    7.3 - Connection Protocols
8.0 - Example Init Strings
    WILL BE HERE
9.0 - Legalese

# marks a MAJOR change or NEW section


0.2 - PreRamble

Thanks all who pointed out errors, helped clarify a few points, sent submissions, posted questions and/or answers, etc... whilst this document was being prepared. Of course any errors and omissions still present are all my fault and any suggestions are welcome at

dtm-FAQ@pierrot.co.uk

This is the first "release" version, posted to demon.answers as well as demon.tech.modems, followups are set to demon.tech.modems as usual.

0.3 - Changes

MINOR a couple of typos and some small clarifications
TODO  Glossary (suggestions welcome)
      Init strings for various modems
      Modem recognition guide!
      HTML version
      Expanded References

0.4 - Why are we here?

0.4.1 - What is the purpose of demon.tech.modems?

>From the FAQ: *** Which News Group? ***
demon.tech.modems       Modems & non-Internet comms software discussions
Please note however that if your comms software question is platform specific (especially for some of the "minority" platforms, or if it's a particularly obscure application) you may well be better off asking in the demon.tech.platform group that is most appropriate. Please see the Which News Group FAQ for help in deciding where to post.

0.5 - Do I have a problem?

0.5.1 - What is the source of the problem?

The first thing you need to do when you think you have any kind of connectivity problem is to try and track down the cause. The best place to start is Demon's "status", finger status@gate or check the Web site.

Then read though the last couple of days of demon.tech.modems and any other Demon support groups you take. It may be that it's a known problem. If it doesn't seem that other people are currently experiencing problems then it's worth checking your setup.

See Section 4 for some common connectiviy problems and Section 5 for a discussion on how to test speed.

0.5.2 - Where do I report problems?

You could try posting to the newsgroup demon.tech.modems, or emailing Demon at either
helpdesk@demon.net or dialup-faults@demon.net
depending on the type of problem, and what response you want.

Helpdesk is the email equivalent of the 24 hour phone support (0181 371 1010) and is in fact answered by the same staff!

Dialup-faults is mostly an address that is used to collect information, you are unlikely to get any direct response from a report there. However your report combined with those of other users can be very useful in helping solve general dialup problems.

0.5.3 - How do I report problems?

The following information can be of use both in the newsgroup and in fault reports to Demon.

Exactly what setup is in use (PC Spec (hardware/OS/stack summary, Modem including any ROM or other version info., speeds, init string, type of line (BT, Mercury, Cable), calling xx from xx, times, dates, which line you logged into an dthe version of the firmware being run on it - you should see these during the CONNECT/LOGIN, weather conditions at the time)

Results of pings, traceroute and similar debugging tools. Or logfiles that help put the problem in context. These should all preferably be copied/pasted or otherwise included verbatim to help avoid any problems with typos. Please note that many mail/news packages will encode such things if they are "Attached" so they should be "Included" instead.

Important:
What you were doing at the time. i.e. http, telnet, ftp, gopher, news, etc., one or more at once, what URL.

Applicable software installed, such as Office 95/97, browser(s) installed (including version number), browser in use (if applicable), ftp software in use (if applicable), etc.

Any phone extensions and equipment on the line.

And of course any results from the checklist that you think may help others work out what's going on.


1.0 - References

Miscellaneous sources of further information, some of which is a pre-requisite for understanding modems, others expand on many of the questions/answers below, some give detailed technical explanations of areas that have been glossed over.

modem.txt is in my opinion essential even though some of the specifics are mostly out of date.

The Tuning FAQ was written primarily for the KA9Q software, but contains many general tips for improving the performance of your comms link.

And again though fairly old, How to connect to Demon reliably has much general help on the "black art", and isdn.txt is a quick discussion about what ISDN is all about.

Other sources of useful information that are specifically modem related are The J Navas FAQ, also available as a uuencoded zip file by sending an email message to

ModemFAQ@NavasGrp.Dublin.CA.US with a Subject of "send modem
faq".
Note: Also by J Navas, a comprehensive list of manufac turer Web sites.

Try www.56k.com/firmware/ for a page of links to firmware upgrade sites for a long list of modem manufacturers, or if you're having problems identitying your modem, then fccenter.html may help.

Or just try www.manufacturer.com ! (substitute your modems manufacturer)

For information about 56K technology, start at www.56k.com and an FAQ about K56Flex modems can be found at www.unicorn -connection.co.uk, while a list of UK ISPs can be found at www.limitles s.co.uk

Another very useful resource is the DIS Meta FAQ which has many handy hints on where to find useful information and the best places to start looking for help on many problems.

And of course if you've got a problem it's always worth checking demon.announce, status@gate, the Demon help desk.

Several of the Demon specific documents mentioned are always available on the Demon Web site.

Connect by
Modem
Connect by
Orange
Connect by
ISDN
Connect by NDU
(Networked Dial-Up)
Modem
Connections
Frequently Asked
Questions about Ascends

2.0 - General Questions

2.1 - What kind of modems do Demon use?

They don't!

What they do use are Ascend Terminal Servers, see www.ascend.com

For most purposes however these can be regarded as black boxes that look like modems when we connect to them. In fact so that they can deal with the analogue modems in general use they have "modem cards" in them. If used with ISDN however they are "fully" digital. See the Ascend Web site for further details.

You may see the Ascends referred to in a number of ways, TNT and MAX are both model names. You may also see them called "not modems".

2.2 - Do I have a problem with my modem?

Please clarify the problem...

But seriously, there are certain pieces of information that are vital to solving any given problem, and there are some that are generally useful. So please, in any initial post to the group asking about a problem with a specific modem or piece of software, give as many useful details as you can about your setup and the nature of the problem. See Section 0.5 for examples of information that may be of use.

2.3 - How do I find out the ROM version of my modem?

Win95 users can get this information from
Control Panel/Modems/Diagnostics/More info
A more generic method however is to start up a general Comms/ Terminal package.

For Hayes/Rockwell modems these commands give the firmware version of the ROM, the modem model and the data pump version.

ATI3
ATI4
ATI6

USR modems use ATI7.

2.4 - How do I use a Comms/Terminal package to get this information?

It's a program that allows you to "talk" to your modem directly. Fully featured programs will also include automatic dialers, terminal emulation and so on. They are available on many platforms, either as part of the OS software, commercial or public domain.

Windows3.x users should have a program called Terminal. Some have reported problems using Terminal, if you can't get it working try www.delta.com and download the shareware version of Telix for DOS.

For 32-bit Windows try the supplied HyperTerm. One important thing to note with HyperTerm is that you need to use the "Direct to COM#:" option when you start it up (where # is the number of the com port that the modem is plugged into of course!).

Alternatively do a search for a program called kermit, there are versions available on a multitude of platforms.

Once you've located such a program for your platform, follow the setup instructions and you should be presented with some kind of command line prompt. Try typing ATZ then Return/Enter, the modem should come back with OK. If not, ask on the newsgroup!

2.5 - What are all these AT commands anyway?

Your modem should come with some documentation detailing what all the commands do. Of course it might not, if your modem uses a Rockwell chipset then the site www.rockwell.com/ should help.

And of course since Hayes originated the ATtention command set www.hayes.com is also a good source for general information on them.

USR users should try

www.usr.com
www.usr.co.uk
Or email uksupport@usr.com

2.6 - I've RTFM and I still don't understand what these AT commands do

OK, there are a few commands that are used a lot, here's a brief description of a few of them.
In use they should be preceded by AT, though you only need one AT per line (note that there is a limit on the length of the command line with at least some modems, tests here have shown it to be in the region of 55 chars).

Some fairly generic commands:

DT#######   - dial tone the number #######
,           - pause for 2 seconds
H?          - go on/offhook
&F          - reset the modem to factory defaults
Z?          - reset the modem to the last settings, or to the ?th
W?          - write the current settings
Sn?         - return value of status register n (NB that many of
            - these registers are model specific
For Hayes/Rockwell firmware
&V          - see how the modem is setup
&V1         - see some information about your last connect
I3          - firmware version
I4          - product name
I6          - data pump version
\N?         - is for setting error correction mode
%C?         - is for setting compression mode
see also the K56Flex section for some other commands.
And for USR
I3 = Product Type
I4 = Current modem settings
I5 = NVRAM settings
I6 = Link Diagnostics
I7 = Product config.
&M?         - is for setting error correction mode
&K?         - is for setting compression mode

2.7 - The modem always answers calls before I can!

This is known as AutoAnswer, you can disable it by starting up your terminal program and typing ATS0=0&W (the S0=0 turns it off, and the &W stores this in the modem so you won't have to do it again tomorrow..)

3.0 K56Flex, X2, 56K

3.1 - Which versions of 56K technology are supported by Demon?

Today, none.

However once the new standard, V90 (AKA v.pcm) has been ratified by the ITU, and there are "modems" available to Demon that implement that technology, then they will support the standard. See also www.56kstandard.com and www.v90.com for the latest news.

The current situation is that the major players have agreed the standard in principle. Target date for full ratification is September 1998. Many manufacturers are promising beta versions as early as March 1998.

Demon may configure the test number to run beta-versions of the forthcoming standard as Ascend (or possibly other manufacturers) make them available, however they will not do this until it has been proven to work. Even then though it will not be a "supported" service.

3.2 - Which versions of 56K technology are usable with Demon?

K56Flex is enabled on the test number, 0845 079 8668, as of the writing of this FAQ. This is likely to stay enabled unless it causes problems with testing. Note however, Demon may turn K56 off at a moments notice, and not restore it for several weeks. Or in another case recently K56flex was disabled for the weekend before the code was transferred to the main numbers "just in case".

It is unlikely that X2 will ever be usable with Demon, however many manufacturers of both X2 and K56 modems have promised that their modems will be upgradeable to the new standard.

3.3 - Which 56K modem should I buy?

The short answer is none. However, as noted above, K56flex may work. There have been varied reports of connect speeds, problems, etc... with most of the popular models when connecting at 56K.

Additionally it should be safe to buy any modem that claims to be cheaply (or freely) and easily upgradable to the ITU standard. Of course both the K56Flex and X2 modems available should work with Demon at v34 now.

And obviously if your old modem has just died, or you're upgrading from a non-v34 capable modem then it may make more sense to buy a flashable 56K model. A flashable modem is one that contains a ROM which can be upgraded by software. In most cases you just connect the modem to your PC as normal and run a program which does the upgrade.

3.4 - Where do I get a flash upgrade for my modem?

In general most modem manufacturers have a web site or bulletin board where they post the upgrade files.
Motorola: 01293428490
Hayes: 01252775599
The best place to ask is where you bought the modem from! Or try the References section of this FAQ.

And it is often well worth getting the latest upgrade, e.g. v1.120 has increased many Motorola users connections by 4000.

NB: though that it is unlikely that V90 updates will connect to (m)any ISPs for a while. Wait until you know your ISP supports V90.

3.5 - What is the "best" init string for my modem?

A very difficult question, however...

Try the default settings first, they work well in the great majority of cases. If you are unsure as to how well your settings are working, then test the setup out as per "The Need for Speed". For those unfortunates for whom default settings do not work well, there are a wide range of possible causes and so finding an init string that helps can be a difficult problem.

Technology has changed over the years (modem protocol standards being widely used, better quality phone lines, etc...), and unless they have a specific problem most people find that changing the default values (or those setup by a .inf, .mdm or similar) only results in worse performance.

The reason that there is no "best" init string (and indeed why init strings are changeable by mere users), is that when modems try to connect they use a very sophisticated protocol which probes the characteristics of the connection before choosing one of a number of variants of the modulation scheme. For a few users who have problems, the eventual solution may be to make settings to restrict the choices that the modem makes in order to exclude choices which appear plausible, but don't actually work well in practice for this particular modem or phone line.

See Section 8.0, there may be an example init string there for your modem. Many other sections of this FAQ are aimed at isolating any possible problems, once you've done that it may be possible that an init string could help you.

However here is some general advice on how to construct your own init string.

3.6 - And what are these new AT commands?

For Hayes modems,

%E0     Disable line quality and auto-retrain.
%E1     Enable line quality monitor and auto-retrain.
%E2     Enable line quality monitor and fallback/fall forward.
+MS=11,,,,, - force v34 connect
+MS=56,,,,, - force 56K connect
The following is recommended for a K56 connect
+MS=56,1,34000,56000
and S91=15 has been known to improve some users' connections.

No such strings are needed for X2. Exactly how this will be implemented in practice in the V90 standard is yet to be seen.

Forcing a v34 connect can be useful in some circumstances. e.g. several of the recent software versions on the test number were causing "Loss of Routeing" type problems with my modem if I connected using K56, but not using v34. These went away with release 1.3ap20 of the Ascend code. This version number can be seen between connection and login to the Ascends, e.g.

test-finch-237.access.demon.net (2.0.0)
Note that this is very useful information if you're reporting a fault.

3.7 - Where do I report faults with the test number?

Assuming they're K56 specific, k56flex-test@demon.net. Note however that Demon are not supporting K56 officially. See above re: forcing a v34 connect, it's well worth checking this before reporting a fault (if things still don't work the address is dialup-faults@demon.net).

4.0 - Slow, Dropped and No Connections, Network Death, Loss of Routeing

4.1 - I only get xxxk/s from Demon, why?

Well there are several possible reasons, mostly outside the scope of demon.tech.modems, e.g. "bandwidth" problems. The only speeds we can be relatively sure are usable for testing is when downloading known files directly from Demon by ftp. See Section 5 for details on how to test your connection speeds.

4.2 - Overruns & Errors

If you are getting low download speeds, with a high CARRIER and CONNECT, then you may be suffering from Overruns. Ask in the appropriate ip.support group for details of how to check this. (Turnpike users see it as "Errors" in the Connect window, and should look up Errors in their Help File).

An overrun occurs when your computer can't receive data from the modem as fast as it's set to. And even though it may only be one character that has been lost it is necessary for the whole packet (500 bytes+) to be resent. And all this takes extra time.

If you are getting overruns the first thing to try is reducing the DTE. In general this should be set to ~ max CARRIER * 4 if possible, e.g.

v34 modem - 115200
v32 modem -  57600

However it is only rarely that you'll ever see throughput this high in normal situations, so you won't lose much by reducing to 57600 or 38400 respectively.

56K modem users may be able to set DTE=230400, however most standard PCs cannot currently handle that.

A lot of overrun causes are hardware (or software) specific, as are solutions to them. However there are some general areas that can be checked.

And of course users of all platforms may need to reduce the overall load on your machine whilst you're connected to the net. Any program requiring disk or CPU usage may be causing the overruns.

4.3 - Why did my connection drop after x mins?

There can be several reasons, the first question is always, was there any traffic at the time. Your setup and Demon can have timeouts set (at Demon it's typically 4 mins but can be overridden at the Protocol: prompt by idle=n where n is in secs) see the ip.support group for your platform for details of how to set this, or any other, timeout.

If there was traffic flowing then it may be due to a bad connection. Many modems have both AT commands and S register settings that can modify how they react to a momentary loss of carrier.

If you have Call Waiting an incoming call can make the modem drop the line, similarly so can the "pips" on payphones.

A few other points that may also be worth noting are

And remember to take a look at your logs. The modem you are using may be able to provide a good source of information, both current and over the total connected time, on both statistics and quality of line.
Alternatively, if you are using Windows 95 DUN (Dial Up Networking), you can produce a modemlog.txt.

Noting down your results to these points may help you build up a picture of what may be going wrong. Even if it doesn't, it may help to include these details in any fault reports to Demon or to the newsgroup (see Section 0.5), at a minimum it will save wasted time (it's likely that people will ask you to check these things!)

Another possibility is

4.4 - What's "Loss of Routeing"?

It means that somewhere between your computer and the server that you were connected to, that data is effectively getting lost. There's no known path between them anymore (see demon.ip.support for a real explanation). When this symptom spreads and you find that you cannot get any data from any site you get something resembling Network Death.
If you can get any response try using traceroute to the server that you're trying to connect to (of course you might not be able to due to the nature of the fault). If that fails then try

ping 158.152.1.222           - if this works then your connection
                               is still up
ping demon-du.demon.co.uk    - if this works then either you've got
                               the address for demon-du cached, or
                               DNS is working
ping gate.demon.co.uk        - again as above, but also data is
                               getting past your gateway (if it fails
                               it may be because gate is down so try
ping post.demon.co.uk        - as above
telnet post.demon.co.uk smtp - you should not only get a connection,
                               but also a welcome message, if this
                               fails then it may well be ND

"Loss of Routeing" is a specific issue with the routers at Demon (which have lost the dynamically made static routes from the Ascend to the rest of the Internet). Note that it is unlikely to be caused by your setup, and in most cases the problem won't recur (though as usual it's worth checking status@gate, the problem may have been widely spread enough to be reported).

This can then cause Network Death. As can the Ascends getting detached from the Ethernet they live on, or a fault in the Ascend or... or almost anything.

4.5 - What's Network Death?

Very similar to loss of routeing in symptoms, typically with your modem sending the ping request to the server (see the SD light on external modems), but without reply (no RD light). This may be a transitory problem at Demon, or it may be down to some incompatability between your setup/modem/phone/Demon. Some specific models have been known to be more problematic than others (Motorola 3400 is top of the list). But Demon/Ascend/Motorola/Others have been working on sorting out the problems.

If you think you are suffering from this problem then try connecting to the

COLT ROMP (08453535666)
Energis ROMP (08450798666)
Local Energis number (see pops.html ) and
Test number (08450798668).

You may well find that your modem works fine on some numbers but not others. Either way remember to put the info. that you have tried different numbers in any fault report. For one thing it'll stop people suggesting that you do so... And it can help Demon create some kind of pattern (if possible) of the problems.

A lot of discussion has been going on in the various demon newsgroups for a while now, with Demon admitting that a problem does exist with the minority of it's customers, and that a solution is being worked upon in co-operation with Ascend. It is probable that the cause is either a problem with your setup, telecom connection or a temporary problem (e.g. maintenance) at Demon, especially if the problem is of an intermittent nature. It's always worth checking status@gate and/or contacting Demon HelpDesk by either email or phone.

However if you're still getting these symptoms regularly after checking out the possible causes of connectivity problems detailed in the section above then it is likely that you're a sufferer.

One other point of interest is that some users have reported that if you can get an external site to "ping" you whilst it's happening then the problem disappears.

Reports of "Network Death" problems should go to

dialup-faults@demon.net

It would be helpful statistically to cc (Carbon-Copy) your reports to net-death@cyberstorm.demon.co.uk. This is the address of a Demon user who is particularly interested in this particular problem and who may be able to help. (incidentally he wrote a lot of the above section :)


5.0 - The Need For Speed

5.1 - How do I tell what speed I connected to Demon at?

The modem should report what speed it connected at, however there are several different ways it can do it. This is further complicated for users of Microsoft DUN by .inf files that translate this information (see section 6.1).

In general most modems have AT commands and S register settings that allow you to modify the format of the reply code. If these don't give you the information you want then try using the Link Diagnostics for your modem type after dropping the connection.

5.2 - How fast should I be able to download files?

That varies dependant on several factors.

And usually most of the factors are not only outside our control but also outside the scope of demon.tech.modems and therefore this FAQ. These include issues such as bandwidth, load on servers, etc...

What we can help with though are ways of testing how well your modem is setup for use with Demon. First of all, please read modem.txt, and use support@demon.net, from which I quote


" Alternatively, you can request help documents for a wide range
" of topics, by emailing support@demon.net and supplying the
" following subject line (in lower case only please):

" Subject: send filename

" where filename refers to the document you want, eg.windows.
Filenames that are of particular interest include

" ascend             Information on connecting to an Ascend server
" isdn               Information on using ISDN to connect to Demon
" modem              Configuring your modem for an Internet
connection
" tnt                Using very old modems on the Ascend TNT's
" ftp                How to use FTP to transfer files
" ftpdemon           How to transfer files to and from Demon's
servers
and of course any platform specific files, or FAQs as appropriate (see the MetaFAQ).

Now you've got your modem setup as best you can using the above it's time to test it. And hence the reason for getting the ftp help files. To do this kind of testing you need to be connecting to ftp.demon.co.uk from a Demon node and not running any automatic news/mail collection, or in fact any other up or download. It's also best to do this testing when Demon are not likely to be heavily loaded.

OK, start up your FTP program, connect to Demon, cd /pub/test There are several files in there
fullfile
emptyfile
regularfile
Also check the new and rockwell subdirs which contain
htmlfile
newsfile
basefile
vfullfile

Download speeds should vary markedly between most of the files (unless you're using ISDN in which case they should be 7.24K/s assuming a single 64K channel). Some of these speeds are purely of intellectual or indicative interest, some however show the maximum speeds you can download files.

emptyfiles - max = CONNECT/divisor
fullfiles  - max = CARRIER/divisor
the rest   - max is somewhere between the above 2

Where CONNECT is the computer-modem (or DTE) speed, which is set by you in your software. Generally the higher it's set the better, however if your setup is not capable of supporting that speed your downloads will be slower. See Overruns elsewhere in the FAQ.

And CARRIER is the modem-modem speed. Generally your modem should be set to negotiate the highest speed it can. Sometimes this, like the DTE, can cause more problems and you may need to limit the CARRIER (most likely cases currently are 56K modems, see the 56K section for details).

The divisor can vary, see modem.txt for why it's not always 8. For emptyfile the limit should be CONNECT/10 , this is because the async bytes are sent 1 start bit, 8 data bits, 1 stop bit per byte at the DTE rate.

Empirically PPP has shown figures very close to the above (emptyfile at CONNECT/11, fullfile at CARRIER/9), SLIP has been slightly worse. CSLIP should give figures similar to PPP.

Another factor to consider is where you retrieve the file to, e.g. /dev/null, NUL: NIL: may give slightly faster speeds (though obviously that's not much use for real downloads!)

Now onto the reason why fullfile uses the CARRIER, and emptyfile uses the CONNECT. It's all down to modem compression, assuming it's enabled on your modem, and everything else permits it!

Basically fullfile is not compressible at all, hence no gain over the CARRIER. emptyfile however is very compressible, so much so that even with a 28800 CARRIER it can still be received at in excess of 115200.

So emptyfile is a test of the modem compression and the DTE, fullfile is a test of the maximum number of bytes that can be received per second.

Speed tests done on a 54000 CARRIER using a DTE of 230400 have shown emptyfile/regularfile topping out at 16K/s. It is not known at present what has caused that limitation. It may be the compression algorithm, it may be bandwidth from ftp.demon.co.uk.

Please note that these are only indicative speeds, you are unlikely to achieve them in real world usage. But if your modem/setup comes close to the theoretical max speeds above there should be no need to try and tweak things any further!

5.3 - Why is COLT so much slower than Energis?

The COLT ROMP is using (in the main) different Ascends running a different version of software than the Energis numbers (there are also a few other setup differences). Note that some new Ascends have been added to the end of the COLT search group, so it is possible that you'll get a "TNT" rather than a MAX4000 on a connection to COLT at busy times.

And of course the different ROMPs also terminate in different parts of the network. This should not under normal circumstances affect overall speed (Demon have a 155Mb link between their 2 main sites).

Similarly some of the ISDN lines may answer calls to the 5666 hunt group when demand for ISDN is low and demand for Energis is high (typically early evening). So remember to note the id of the Ascend that takes your call as well as which number you called.


6.0 - Setting Init Strings and Modem Responses (32-bit Windows)

6.1 - Why does my modem claim to connect at 115,200 bps ?

This is the DTE rate and is reporting the speed of your com port setting (the speed at which data can flow between your modem and your computer). In order to display the initial connection speed it is necessary to use an appropriate command in your init string to display DCE (modem to remote modem speed).

Windows users should note that the use of an out-of-date modem .inf file for a high speed modem can result in DTE always being displayed instead of DCE.

It's worth checking the manufacturers Web site for the latest .inf file. If that doesn't help, and you really need to see the actual CARRIER value there are ways to change the .inf files.

This does not affect users of Turnpike 3.04 and before if they have TP set to use its own Connect program. However from v3.05 onwards it uses Win95 DUN, so it will also affect those users.

Also note that as long as your setup doesn't force a modem reset, and consequent loss of information, you can often find details of the last connect using some of the AT commands detailed in section 2.6.

6.2 - How do I change the modem init string in Turnpike?

Turnpike (apart from version 3.05 for Win95) drives the com port directly, using a *.mdm file that contains the init string. The universal modem file works well for most modems, and should not be altered, but *.mdm files for specific modems can be altered in a text editor.

6.3 - How do I change the modem init string in Win95

Control Panel/Modems/General/Properties/Connection/Advanced/Extra Settings

Those migrating from Turnpike 3.04 to 3.05 can extract the old init string from their old Turnpike .mdm file. This will be in the Turnpike install dir, simply open it in a text editor and cut/paste the init string. Remove the \r from the end of the line, and replace all occurences of \\ with \

6.4 - AT&V1 gives no last connect info

Some modems reset this info. on receipt of ATZ. And some dialers send an ATZ after hangup (DUN is one). The fix for DUN is to run the Registry Editor, "regedit", and disable the reset by editing the "Reset" key in
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\Modem\0003
                                            or some other number-^^^^
                                   (whichever key refers to your modem)
to show "AT<cr>" instead of "ATZ<cr>"

6.5 - How can I see the "CONNECT" (DTE) speed with DUN

The fastest way to see the initial connection speed is to hover your mouse over the DUN icon which appears in the Win95 tray (on the RHS of the Start menu bar) when you are connected, or right-click on it. A more detailed output can be obtained by selecting "Record a log file" in Control Panel/Modems/General/Properties/Connection/Advanced
The information will be recorded in "modemlog.txt" in the Windows directory.

7.0 - Misc. Stuff

7.1 - Modems, Soundcards and Phonecalls

If your modem is one with 'speakerphone' or 'voice' functions, then you're in business- read the manual (on-line or paper) for details appropriate to your modem. And appropriate software should have been included in the box.

The modem should be able to connect to your existing sound card for complete functionality, but most have their own microphone and speakers (or at least sockets for them).

If your modem is not one of these, then in all likelihood you're out of luck since the modem would need some special hardware and firmware in order to route the sound in and out of the phone socket, and through various other magic things.

7.2 - Caller ID

There are (at least) two forms of Caller ID in use by telcos in the UK. And different modems can read different forms of it.

e.g. USR Sportster Vi is only capable of reading the CLI delivered by the Bellcore system (as used in the States, and also by *some* UK cable telcos). Some Pace and Hayes models (always check first!) are capable of reading the CLI delivered by the BT system (which is also used by some other UK cable telcos).

The two systems are totally incompatible; the Bellcore one sends the data between the first and second rings, whereas the BT design sends the data *before* the first ring. It is also capable of sending more data than the American scheme. (Please do NOT refer to it as "UK CLI" however, since both the BT and Bellcore systems are in use in the UK.)

If CLI arrives, it will be presented as an ASCII string *after* the first RING indicator (even with the BT system, where the data arrives before the first ring; both Pace and Hayes, the only other modem manufacturer capable of handling BT CLI, do this for compatibility with software, such as TAPI, written for the B

And please note that 1471 is not the same as CLI delivered. You have to order it from BT, and PAY for it. (check for any current offers that BT or your telco may have on the service).

7.3 - Connection Protocols

Protocol negotiation: V.8

This is the initial phase of modem connection where they try to negotiate the optimum settings for the connection. This is based on init settings of both modems and the line quality of that connection.

Data modulation: V.32bis, V.34, 56KFlex, X2

What method is used to transmit the data. This is the base "speed" commonly known as the CARRIER. This is setup during the negotiation phase.

Error correction: V.42, MNP4

What method is used to check that any data sent is not mangled during the process. This is setup during the negotiation phase.

Data Compression: V.42bis, MNP5

What method is used to compress any data sent. Note that the different methods of compression have varying results on different files. This is setup during the negotiation phase.

Link protocol: PPP, SLIP, CSLIP

PPP = Point to Point Protocol
SLIP = Serial Line Interface Protocol
CSLIP = Compressed SLIP - note this is packet header compression not data compression

Nothing to do with the modem, it's defined by your dialing software. Demon supports both SLIP and PPP, some client software may allow you to use both, some only one or the other.
There are various advantages of PPP, in tests it's faster than SLIP, but about the same speed as CSLIP. And Line Quality Monitoring is also available (see a platform specific ip.support newsgroup for details about your software).

Network protocol: TCP/IP, IPX

Again, nothing to do with the modem, it depends what software you're using. Typically most dialup users will use TCP/IP most of the time. Some games, eg Network Doom, use IPX.


8.0 - Example Init Strings

WILL BE HERE!

I already have a few, I'm just trying to work out a good way to both present them, and store them for reference. Any ideas or init strings - preferably with an explanation of why anything out of the ordinary has been done.


9.0 - Legalese

(which may bear more than a passing resemblance to that used in the dis.newuser FAQ :)

The advice given in this FAQ is of necessity generalised, so you follow it entirely at your own risk. Always back up valuable data! The details have been carefully checked, but the Internet develops at a rapid rate. Things will probably be inaccurate or out of date and I apologise in advance. I welcome corrections whether they be factual or simply typo's or matters of grammar!.

The original author (Tez Boyes) has no commercial interest in any of the products or services mentioned. My motive for writing this FAQ is to try and help keep the noise down on dtm (especially re: 56K!) as well as providing a useful reference for common questions and helping other users not only get the best from their modems but also understand why to some extent...

Our thanks go to the many posters to Demon news groups, who have helped shape my thinking (references to FAQs and other documents they have written are aplenty above!), and particularly those in dtm who helped review the original draft and to all those who have sent me suggestions (even sections) and comments.
Unfortunately they are too numerous to list here and I'd be bound to forget at least one, but they know who they are (and anyone reading the newsgroup for any length of time should recognise the contributors!)

If you have any corrections or suggestions for improvement of this FAQ, please email the following:

        Tez Boyes

However please direct any questions not covered in the FAQ to the newsgroup (whence I can glean the answer for the FAQ :)

This document may be freely distributed provided that it remains unaltered from its current form.

Copyright 1998 Tez Boyes

--
Team AMIGA