We are trying to reach real-time 50mS per round trip of 20 byte TCP messages of receive and then send response. I'm actually seeing closer to 150mS round trip time. Much of this time is taken up in switching between data and command mode. Our measurements indicated 88mS or 44mS per side. Switching to command mode requires the following characters Tx:"at+s" and Rx:"+WIND:59:Back to Command Mode". At 115,200 bps that's 0.00295sec at 10 bits per char which is 6.8% of 44mS delay. What is the other 93.2% of the delay time? How long should it take to switch from data mode to command mode? This appears to be putting excessive overhead on our message traffic?