PCMCIA/modem: trouble with `chat'

[Jerome Benoit <JGMBenoit@Wanadoo.fr>]

I have some trouble to set PPP:
when I `pon', `chat' exits with the fatal error:
"Can't get terminal parameter: Input/output error"

How can we resolve it ?

Thanks in advance,
Jerome.

my debian box:
debian version 2.1, kernel 2.2.1,
ppp-2.3.5-10.