Bad Ports or something else?

We are using a PortServer TS 8 MEI. We believe we have all 8 ports configured identically (RealPort). However, on this particular unit we have found that five of the 8 ports appear to communicate correctly (3,4,5,7 and 8) with our setup while ports 1,2 and 6 don’t work as expected. We set up a pair of Hyperterm terminals with a null modem in the cable between the computer and the TS. We then attempted to send ASCII characters from the computer to the terminal server and vice versa, switching from port to port as we perform tests. On the five functional ports we can successfully transmit characters in either direction. However, on the other three ports, we can transmit characters from the TS to the computer (but with character echo also observed on the TS Hyperterminal even though local echo is explicitly turned off)… And in the other direction, from the computer to the TS, we cannot send characters at all for the three above mentioned ports. We don’t think it seems likely that these 3 ports are damaged (though maybe??) so we keep thinking something isn’t configured correctly… We’ve power cycled many times and also rebooted the TS multiple times but to no avail… Anyone have any ideas what might be going on?? What settings could cause the above behavior, if any??? Or what troubleshooting techniques we might be able to employ??? Any help would be much appreciated… thanks much… bob…

The best way to check the port integrity is by running a loopback test using the loopback plug shipped with the product:

Also, sending the configuration from you unit may help to determine whether there are configuration differences between the working and non-working ports.