Library /sys$common/syshlp/tcpip$telnet_help.hlb SEND, SYNCH  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The SEND SYNCH command clears the communications path between
    your local system and the remote host. The SYNCH is sent in
    urgent mode (out-of-band, OOB). As a result:

    1. The local host immediately sends an interrupt character,
       placing it at the front of the data stream sent to the remote
       host.

    2. The remote host immediately processes the interrupt character,
       ignoring any incoming data not yet processed, and then
       including a TELNET synchronization or interrupt character
       in the data stream it sends back to the local host.

    3. The local host throws away all incoming data (rather than
       processing that data) until it detects the synchronization or
       interrupt character. This provides faster response time to the
       synchronization and interrupt characters.

    DCL-Style Format

      SEND SYNCH

    UNIX Style Format

      send synch