User`s manual

U.S. Robotics I-modem Command Reference
Appendix A: Alphabetic Command Summary • Page A-19
&M5 ARQ asynchronous mode. The I-modem hangs up if an ARQ connection
cannot be made.
&M6 V.25bis synchronous
mode using a character-oriented link protocol similar
to BISYNC.
&M7 V.25bis synchronous mode using the HDLC link protocol.
&Nn Connection rate variable or Þxed (analog connections only).
&N0 Variable rate. The I-modem negotiates with the remote device for the high-
est possible connection rate, depend-ing on the capabilities of the remote
device.
&N1- &N16 Fixed rate. The I-modem connects only if the remote device is oper-
ating at the same rate. You can use this feature to Þlter out calls at other
than a speciÞc rate for security or other reasons.
The connection rate must always be lower than or equal to the serial port
rate.