Analog Communication with cFos

Calling In Analog Mode (via Modem)

Before trying to use cFos to call an analog modem via ISDN, please make sure your ISDN card's CAPI driver offers this function. You can find out by entering "ATI" as a command in whatever terminal software (such as Hyperterminal or Telix) you may be using.
This should prompt cFos to return information much like the following:

cFos/NT 3.51 -- Windows NT COM Port Emulator for ISDN CAPI 2.0
Copyright (c) 1993-2000 Martin Winkler, Chris Lueders

Licensed to Order cFos!, Bonn/FRG (email@test.com) [cF4242]

RX-bufsize: 12288 CAPI by: AVM-GmbH
TX-bufsize: 12288 Version: CAPI 2.0; Rel 3.06-11
B2-framelen: 2048 S/N: 000001a
B2-winsize: 4 Profile: G=39 B1=11f B2=b1b B3=bf S=f

CAPI: Modem=2 Fax=2 V.110=1 V.120=1 X.31=1 V.42bis=1
cFos data compression: Off
ATM broadband support: Disabled
PPP maximum receive unit (MRU): 2048 bytes

Please check the entry in the fourth line from the bottom: If MODEM=0 is returned, your ISDN board's CAPI does not support analog modem calls. Otherwise, if MODEM=1 or =2, cFos can switch to analog mode.

In case your software uses Windows modems, please install the modem called "cFos ISDN, Analog Modem Support" by starting the "Modem Manager" under "Settings -> Control Panel." Click on "Add", then check the "no automatic detection" option, and select "cFos GmbH" as the manufacturer. From the list on the right pick the "cFos ISDN, Analog Modem Support" modem. Then enter which port you configured for cFos.

You should now be able to use your modem to establish an analog connection.

If you want to use DOS, OS/2 or any Windows software not supporting Windows modems, you will have to add an ATB7 command to the modem init string of that software. This will put cFos in analog mode. If your CAPI driver relays this kind of data to cFos, you could for instance view the bit-rate of your connection using AT &F X9 B7. Otherwise, CONNECT 14400 is displayed.

Accepting Analog Calls (Modem)

First of all, you need to tell cFos to which number it should react or, in other words, what number analog callers are supposed to be dialing. For Windows versions 3.x, 9x/ME and NT/2k, this number can simply be entered in the "MSN" field.

If you want to modify your present configuration, just go to "Configure cFos" ('cFos Setup' in older cFos versions) and add the number.

Depending on what software you're using, you may also enter the number into the modem init string itself by adding the following to the command line that starts with "AT:"

&A0=123456&E0&L0

where "123456" is the MSN (without area code).

To accept incoming analog calls, use the "cFos ISDN, Analog Modem Support" modem as well. But for this, you also need to enter AT &IAD S44=1 into the "Further Settings" field under "Properties -> Settings -> Extended."

For software that does not work with Windows modems (like DOS, OS/2 and even some Windows software), add the following command to the modem init string:

&IAD S44=1

Now, cFos should accept analog calls as well.

Register S44:

With the S44 register you can configure the Audio Mode for incoming calls:

Modem fine tuning with registers S112 and S113: