9. cfg_ttyI: Configuration of the ttyI* devices (`Modem emulation')

9.1 cfg_ttyI_nomodem: Donīt the ttyI* devices emulate an analog modem?

No! The ttyI* devices just offer a similar communication interface, where all commands are started with AT. This makes it easy to reuse software that was written to communicate with a modem. Communication with a remote analog modem is not possible via the ttyI* devices! The real communication happens in digital, not analog form.

9.2 cfg_ttyI_dev: Which devices should I use for calls out or calls in?

Only the ttyI* devices should be used. The cui* devices are created only for reasons of compatibility. Now that there is mgetty, there is not reason to use the cui* devices any longer. If they are used, locking will not work correctly (several programs could simultaneously attempt to use the same device).

9.3 cfg_ttyI_hdlc: How to I switch the modem emulation from X.75 to HDLC?

With the option S14=3; for example "ATS13=3".

9.4 cfg_ttyI_uucp: How can I poll with Taylor-UUCP using isdn4linux?

As usual, the same as with serial interfaces. Simply use /dev/ttyI* as the device, as the init string for the modem emulation you have to set the correct MSN or EAZ with "AT&Emsn/eaz".

9.5 cfg_ttyI_speed: What speed should I set for the ttyI* devices?

It doesn't matter. The driver internally always uses the full speed that ISDN offers. This is also given in the connect string.