The cable works ok between qpti -> qpti.
Character by Character or under heavy load (e.g. ZMODEM)? The handshake needs to be working.
How many serial ports do you have in the Q40? 2 or 4?
I suggest you write a little BASIC routine which transfers masses of data simultaneously both directions and count and compare to ensure that no character loss occurs.
On my Q40, SERNET worked only on 2 COM ports as the two other ones had interrupt problems and lost characters.
Jochen
