From the ltmodem-2.6-alk-9 source all the references in NEWS, README and udev-setup files are to ttyLTM0. However in serial.c of the ltmodem-2.6-alk-9 it is now created as ttySLTM instead so udev rules to create /dev/modem symbolic link to /dev/ttyLTM0 don't work. Searching, it looks to have been changed for serial port finding routines only look for /dev/ttyS* devices (see URL). Suggest we change the udev rule to match ttySLTM. Not sure on punting upstream. Linmodems mailing list perhaps?
Created attachment 158367 [details, diff] Patch for ltmodem_udev under files.
Fixed in 2.6.9-r1. Thanks!