Entering At Commands In A Terminal Program - ELSA MicroLink ISDN/PCC-16 User Manual

4.2.1

Entering AT Commands in a Terminal Program

If you want to use the AT command set known from analog modems, you must load a suitable FOSSIL
( Fido/Opus/SEAdog Standard Interface Layer ) driver, e.g. cFos, in addition to the CAPI driver. The
cFos/DOS driver shipped with your ISDN adapter board allows the use of communications programs
supporting Interrupt14h or FOSSIL output (such as Telix or Telix for Windows ) and must be loaded in
addition to the CAPI 1.1 driver. The FOSSIL driver emulates the AT command interface in order to
allow FOSSIL-supporting communications programs, which are normally used with analog modems, to
work directly with ISDN adapter boards.
We will use Telix as an example to demonstrate how to enter AT commands in a terminal program.
For operation with your ISDN adapter board, Telix must be set to INT14 mode. This is a special mode
in which Telix directs data output not to the serial COM port, but via the BIOS interrupt 14 which
enables the use of passive ISDN adapter boards via suitable driver software. Note that Telix versions
older than 3.50 do not support the INT14 mode (except for Telix INT14, a special variant of Telix 3.15,
which works in INT14 mode only).
The cooperation between Telix and the ISDN adapter board can be shown as follows:
Telix for DOS (INT14 Mode)
Communications Program
Interrupt 14h / FOSSIL
Interface
cFos/DOS
FOSSIL Driver
CAPI Interface
DSS1CAPX / ISDNCAPX
CAPI Driver
MicroLink ISDN/PCC-16
ISDN Adapter Board
ISDN S 0 Interface
MicroLink ISDN/PCC-16 Manual © 1997 ELSA GmbH
Telix sends your AT commands to the
FOSSIL driver cFos
interrupt 14h.
The FOSSIL driver converts your AT
commands for the standardized CAPI
interface.
The CAPI driver is the software link to your
ISDN adapter board.
The ISDN adapter board is the hardware
link between you computer and the ISDN
network.
Operation in AT Mode
using the BIOS
19