CAPI 2.0 subsystem

modulename: kernelcapi.ko

configname: CONFIG_ISDN_CAPI

Linux Kernel Configuration
└─>Device Drivers
└─>ISDN support
└─>CAPI 2.0 subsystem
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
This provides CAPI (the Common ISDN Application Programming
Interface) Version 2.0, a standard making it easy for programs to
access ISDN hardware in a device independent way. (For details see
<http://www.capi.org/>.) CAPI supports making and accepting voice
and data connections, controlling call options and protocols,
as well as ISDN supplementary services like call forwarding or
three-party conferences (if supported by the specific hardware
driver).

Select this option and the appropriate hardware driver below if
you have an ISDN adapter supported by the CAPI subsystem.

source code:
depends
CONFIG_ISDN

is selected by
CONFIG_ISDN_DRV_GIGASET