Serial interface blocked

One thought on “Serial interface blocked

  1. Q:

    I try to open a data connection with AT#SKTOP, AT#SKTD, AT#SD or FTP with AT#FTPGET, AT#FTPPUT but the serial interface hangs. Moreover when a try to open a CMUX session with AT+CMUX=0,0 I receive the OK only after 5 seconds.

     

    A:

    When one of the socket commands is issued the module enters in data mode
    and HW flow control is activated, since the default setting is
    AT&K3. RTS floating can be sensed as HIGH blocking the CONNECT
    indication into the buffer. The same behavior happens after AT+CMUX=0,0
    and the OK result code is sent out after 5 seconds when CMUX session is
    timedout. To fix it connect RTS to ground or set AT&K0