Cisco is conforming itself to the RS232 standard. This is a serial connection, so it depends on the baudrate. For a standard 9600bps console, I assume that you can use (or at least try) the full 100m cable length that is allowed according to cat5 specs.
Bear in mind that you will probably have two cable ends (one from the module & one from the console on the device) connecting to the patchpanel and that you will have to interconnect these so there could be max. 200m in between the two devices. Although my experience with serial over cat5 is quite good this is most likely too much.
Regards,
Leo
