Hello.

I am coding a fax application, and with one particular modem I found
what seems to be a violation of some of the docs... After I connect
as a 'sender' to a target fax, I start receiving HDLC frames, which
is what I expect, BUT the modem doesn't terminate the data flow after a
(dle)(etx) octet pair!

AT+FRH=3
CONNECT
(...NSF frame...)(dle)(etx)(...DIS frame...)(dle)(etx)
OK

.... while, according to all specs, the modem should buffer the data
and handle it one frame at a time:

AT+FRH=3
CONNECT
(...NSF frame...)(dle)(etx)
OK
AT+FRH=3
(...DIS frame...)(dle)(etx)
OK

Is this behaviour normal and should be accounted for (by checking if
there is an extra 0xFF byte in the buffer after a dle/etx pair?) or
should I complain to the modem's manufacturer claiming their hardware
is at fault? With other modems this doesn't happen.