On Mar 19 2005, 23:43, Jules Richardson wrote: was The complaint about "heartbeat" is because the interface is expecting to see the SQE test appear a few bit times after the end of the frame. "Ethernet jammed" might mean it's seeing a continuous jam signal, or at least sees a jam signal when it listens to the wire to see if it can transmit. A jam signal is what a repeater puts on the wire when it detects a collision (and it would see the SQE test signal as a collision). It's an alternating set of 1s and 0s that lasts 96 bit times, as I recall (an ordinary station can also generate a jam signal but not such a long one), and the object of that is to force everything to see a collision and back off. Now it so happens that 96 bit times is also the interframe gap length, so if you have a repeater with a transceiver set to do SQE tests, it sends an SQE test starting a few bit times into the IFG, then generates a jam which will still be there slightly after the end of the IFG, just when the station might be checking for carrier again. Have you got another repeater somewhere with a transceiver on it? Or are you missing a terminator so that the voltage is out of spec and might look like a collision? one to I've had various DEC machines, like my 11/83, attached to both thickwire and thinwire with non-DEC transceivers and never had a problem. I do check the SQE test, though :-) -- Pete Peter Turnbull Network Manager University of York