Serial port problem on axppci33

[julian.suschlik@gmx.net]

Hi,

i´ve a problem using pppd on axppci33.
After running pon, plog says:
  pppd 2.3.5 started
  abort on (BUSY)
  [...]
  abort on (NO ANSWER)
  send (ATZ^M)
  expect (OK)
  alarm
  Failed
  Connect script failed
  Exit.

Hmm, all cables (motherboard<->serial port<->modem) are ok,
my modem is working fine elsewhere.
"echo AT>/dev/ttyS1" lets the modem-LED flash.
Using minicom there is no response, too.
It seems, my computer can send but can not receive data...
Are there (Milo-, kernel-)options i forgot??
Anyone using serial ports on axppci33|noname ??

thanks
Julian