Telnet and Remote Desktop are both very time-sensitive applications.
Interference, weak signal strength, packet error rate, retransmissions
are all possible factors that could cause a Telnet based application to
lose session.
Collect an AP support info file, when the client is connected and experiencing
problems, in order to analyze reported radio PHY errors, and client statistics.
Do you have problems in all areas, or certain areas?
I suspect poor connections for application issues.