Creates a TELNET terminal device (TNAx:) and connects to a
    network device (BGx:). If successful, returns the TNA device
    name (TNAx:) in the DCL symbol $TELNET_DEVICE. Network input
    and output operations can then be performed through the created
    TELNET device using terminal driver $QIO operations.

    DCL Format

      BIND_SESSION  network_device [ /PROTOCOL=option ]