User`s manual

U.S. Robotics I-modem Command Reference
Flow Control • Page 10-4
&R0 After sending the Request to Send (RTS) signal, pause before sending
CTS. The delay is required by some synchronous mainframes and does not
apply to asynchronous calls.
&R1 Ignore the RTS signal. &R1 is required if your computer or software does
not support RTS.
&R2 Default. Hardware ßow control enabled. The I-modem sends data to your
computer only upon receipt of the RTS signal.
&In Alter software ßow control for received data.
&I0 Disable software (XON/XOFF) ßow control. Recommended for non-ARQ
(Normal mode) calls, but see &I5.
While the I-modem is online, the only characters it recognizes are +++, the
escape code.
&I1 Enable software (XON/XOFF) ßow control. Use in ARQ mode only.