There is a problem with isdn4linux: lsz seems to stop the transmission
after sending some kilobytes.
I've been told that the packet size used in the X.75i protocol defaults
to a too high value which is outside the specification. Workaround:
initialize isdn4linux with "AT&B1024" (some boards can deal with higher
values, maxbe up to 2000 Bytes).

Thanks to Andreas Romeyke <andreas_romeyke@l2.maus.de> and Frank Thieme
<frank_thieme@l2.maus.de>.