AT Commands F-37
AT Commands
Normal mode (\N0) can communicate with nearly any modem. Error correction does
not take place in normal mode.
Direct mode (\N1) does not buffer data and ignores flow control. Also, in connect state,
the serial port always adjusts to the speed of the connection, regardless of the setting
of \Jn. Error correction does not occur.
NOTE
Setting \J0 disables the escape code sequence in direct mode.
Reliable mode (\N2) uses the MNP reliable link to provide error detection and
automatic retransmission of data if an error occurs. This provides for error-free
communications between your system and another that supports the MNP reliable link.
When \N2 is in effect, the modem disconnects if it fails to establish an MNP reliable
link immediately after making a connection.
During an MNP reliable link, both modems should use flow control on the serial port.
When the modem detects a transmission error, it holds data in a buffer attempting to
retransmit.
NOTE
You may not want to use certain other protocols, such as HP Block Mode, with
MNP. Such protocols have particular timing requirements that can interfere with
MNP’s effectiveness.
Auto-reliable mode (\N3) allows the modem to communicate with remote systems that
support the MNP or LAPM reliable link and with systems that do not support the
reliable link. In auto-reliable mode, the answering modem looks for incoming MNP or
LAPM protocol characters from the remote modem. If it detects them within
approximately three seconds, it tries to establish a reliable link connection.
When the modem is set to auto-answer in auto-reliable mode, you can shorten this
three-second period by using the %A command with the \C2 command.