This package includes"i4lfirm"

drwxr-xr-x-     root     root       1024 Aug 04 23:35 /usr/lib/isdn
-rw-r--r---     root     root        396 Aug 04 23:35 /usr/lib/isdn/README.firmware
-rw--------     root     root     259256 Aug 04 23:35 /usr/lib/isdn/b1-1tr6.t4
-rw--------     root     root     264452 Aug 04 23:35 /usr/lib/isdn/b1.t4
-rw--------     root     root       4097 Aug 04 23:35 /usr/lib/isdn/loadpg.bin
-rw--------     root     root      65536 Aug 04 23:35 /usr/lib/isdn/pc_1t_ca.bin
-rw--------     root     root      65536 Aug 04 23:35 /usr/lib/isdn/pc_eu_ca.bin