Multitech MultiModem MT2834MR6 User Manual page 48

&RN Rate Renegotiation
Default: none
The &RN command forces the modem to perform a rate renegotiation while online. To issue
it, you must first escape to command mode by issuing the +++AT<CR> command.
&RR Retrain
Default: None
The &RR command forces the modem to perform an immediate retrain while online. To
issue it, you must first escape to command mode by issuing the +++AT<CR> command.
Chapter 3 - AT Commands
48