Filter
Top Products
AT Commands
Page 31
variable speed mode.
\N3 selects V.42/MNP auto-reliable mode and \N5 selects V.42-only autoreliable mode.
Your modem supports special CONNECT messages for connections made with either reliable or
auto-reliable modes. When the AT\V1 command is issued and your modem connects in either
reliable or auto-reliable mode, a response message will be sent to your computer.
When the AT\V0 command is issued (default), your modem will generate standard CONNECT
messages for both normal and error-corrected connections. If the X0 command has been issued,
the CONNECT/REL will be the only ‘error correction’ response code generated, regardless of
the connection speed.
☞☞
☞☞
☞
Issue the %U1 command if you want your modem to issue CONNECT/ LAP-M
response codes when a V.42 connection is established. The \V8 command will
display details of the error correction and data compression negotiated with the
remote modem. This information is displayed immediately before the CONNECT
message.
The \V9 command will display details of the error correction and data compression negotiated
with the remote modem as well as diagnostic information. This information is displayed
immediately before the CONNECT message.
Improving Performance with MNP 10
MNP 10 is neither an error correction or data compression technique. MNP 10 works in
conjunction with error correction and data compression to improve the performance of your
modem when operating with poor or varying quality telephone lines (as sometimes found with
overseas or cellular telephone connections).
With MNP 10 operating, your modem can automatically resize the MNP packets, depending
upon the line quality. When an MNP connection is established, data is transferred in small
‘chunks’ known as packets. When the line quality drops, MNP 10 reduces the size of packets
being transferred in order to maintain data throughput. MNP 10 will increase the packet size to
take advantage of improved line quality.
If the line quality becomes very good or very bad, MNP 10 can automatically step between line
speeds. MNP 10 attempts to use the highest speed applicable to the quality of the telephone
connection. If the telephone line quality drops while you are connected to another MNP 10
modem, thus introducing errors into your data, and the smallest packet size is being used, the
modems will ‘step-down’ in speed until the error rate become acceptable.
Similarly, if the line quality improves and the modems are using the largest packet sizes, the
modems will ‘step-up’ in speed until the best compromise of error rate and line speed is found.
MNP 10 will also make multiple attempts at establishing an error-corrected connection to
another modem (more so than MNP 2-4). This gives you a better chance of making a connection