I used to use four sangoma wanpipes (S508 perhaps; I'm not sure) on
FreeBSD 2.2.8 (showed up as cpipe0).  I was talking not to a telco T1
but to an EFDATA rf modem in the military UHF band and also over a
satellite, and ran them at 256 kbps.  They worked well; we had very
few issues with them.  I don't remember if we had the kind with the
integrated CSU/DSU; the README claims they look the same from the
driver pov.

I don't know if they support NetBSD, but porting a fbsd driver should
be pretty easy (1800 lines of code and commented even).  A quick skim
of the code gave me the impression the hardware was pretty sane.

One quirky thing is that the driver opens a file in /etc/cpipe (from
within the kernel) to get the firmware on init, and also to load a
config file.  Also, there is a 'cpipemon' program that can get various
stats, which was only (in 1999) provided as a binary.

        Greg Troxel <gdt@ir.bbn.com>