default or selected kernelversion does not have config value CONFIG_HISAX_NO_KEYPAD.
Result is shown for kernelversion 6.9.9
Disable keypad protocol option
configname: CONFIG_HISAX_NO_KEYPAD
Linux Kernel Configuration
└─>Device Drivers
└─>ISDN support
└─>Old ISDN4Linux (deprecated)
└─>Passive cards
└─>Disable keypad protocol option
In linux kernel since version 2.6.20 (release Date: 2007-02-04)
If you like to send special dial strings including * or # without
using the keypad protocol, select this option.
using the keypad protocol, select this option.