PPP connection on a LAN

[Marco Arioli <marco@extern18.risorsei.it>]

This is a little bit OT.
I'm trying to connect my home computer to the LAN of then company where
I work via PPP. PPP server is a linux box running pppd 2.2.0f and both
the modems are U.S.Robotics Faxmodem 56K.
If I use windows95 on my computer it, apparently, works well and I can
http, ftp, telnet without any problems.
If I use OpenBSD 2.5 (i386), just after starting connection I get such a
messages:

Sep  5 21:08:28 pegaso pppd[4946]: pppd 2.3.5 started by root, uid 0
Sep  5 21:08:51 pegaso pppd[4946]: Connect: ppp0 <--> /dev/cua01
Sep  5 21:08:52 pegaso /bsd: ppp0: bad fcs 5264
Sep  5 21:08:55 pegaso /bsd: ppp0: bad fcs f96
Sep  5 21:08:55 pegaso pppd[4946]: local  IP address 192.168.7.199
Sep  5 21:08:55 pegaso pppd[4946]: remote IP address 192.168.7.6
Sep  5 21:09:13 pegaso last message repeated 6 times
Sep  5 21:09:15 pegaso /bsd: ppp0: bad fcs 9f33
Sep  5 21:09:16 pegaso /bsd: ppp0: bad fcs f96
..
Sep  5 21:09:35 pegaso /bsd: ppp0: bad fcs 6c3
Sep  5 21:09:39 pegaso /bsd: ppp0: bad fcs 8e1b
Sep  5 21:09:40 pegaso /bsd: ppp0: VJ uncompress failed on type comp
Sep  5 21:09:43 pegaso /bsd: ppp0: VJ uncompress failed on type comp
sep  5 21:09:45 pegaso /bsd: ppp0: bad fcs d4b2

The connection doesn't work and I can't do anything though routing table
seems OK. Here is the output of 'ifconfig -a' and 'route -n show'

lo0: flags=8009<UP,LOOPBACK,MULTICAST>
	inet 127.0.0.1 netmask 0xff000000 
lo1: flags=8008<LOOPBACK,MULTICAST>
sl0: flags=c010<POINTOPOINT,LINK2,MULTICAST>
sl1: flags=c010<POINTOPOINT,LINK2,MULTICAST>
ppp0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST>
	inet 192.168.7.199 --> 192.168.7.6 netmask 0xffffff00 
ppp1: flags=8010<POINTOPOINT,MULTICAST>
tun0: flags=10<POINTOPOINT>
tun1: flags=10<POINTOPOINT>
enc0: flags=8<LOOPBACK>
bridge0: flags=0<>
bridge1: flags=0<>

Routing tables

Internet:
Destination      Gateway            Flags 
default          192.168.7.6        UG     
127.0.0.0        127.0.0.1          UG     
127.0.0.1        127.0.0.1          UH     
192.168.7.6      192.168.7.199      UH     
224.0.0.0        127.0.0.1          U      

What's the matter? Is it due to a bad /etc/ppp/options or to the server?

Thanks in advance,
Marco.
lock
defaultroute
noipdefault
modem
/dev/cua01
115200
crtscts
debug
kdebug 1
passive
asyncmap 0
user "xxxx"
#!/bin/sh
pppd connect \
'chat -v -t60 "" atx3l0 OK atdt0xxxxxx CONNECT "" ' \
/dev/cua01 115200 modem \
crtscts defaultroute noipdefault debug kdebug 1 user xxxx