I finally managed to get TSS/8 running under SIMH V4... console on the laptop, a time-sharing line (TTIX port 23) on an ADM-3A (much quieter while debugging) :) The interface is the Volpe current-loop to USB board, a small freeware program "COM By TCP" to allow a TCP port (USB is COM4, TCP is 127.0.0.1 port 23). So far so good. But I am having connection problems with the data coming At 110 baud I only get a few characters before the serial-TCP program hangs with this write-timeout message: 22:24:11: Socket connected to 127.0.0.1:23 22:24:11: SOCK: Unable to write on COM. The port is CLOSED.. <-- this is because I didn't "Get COM" first. 22:24:13: COM4 correctly opened! 22:24:24: System.TimeoutException: The write timed out. at System.IO.Ports.SerialStream.Write(Byte[] array, Int32 offset, Int32 count, Int32 timeout) at System.IO.Ports.SerialPort.Write(Byte[] buffer, Int32 offset, Int32 count) at COMbyTCP.Form.sockClient_dataRecived(Byte[] buffer, Int32 bytesRecived) I tried at 1200 baud and the same problem occurs, I can just get more characters before the terminal screen freezes. Nothing's locked up except the downstream SIMH data (i.e. I can hit Return on the terminal and the TSS/8 dot prompt reappears). It is repeatable regardless of what I am trying to do on the terminal. Only very small outputs come through in their entirety without this error message. I don't think it's the current-loop board, which has an onboard micro fast enough to translate Baudot on the fly. And the receive light stops flickering at the same time the write timeout message pops up. Does anyone know how I can extend the timeout parameter... is this a Windows networking problem, or something flaky in the freeware serial-TCP program? thanks Charles --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus