Appendix A AT Commands
49
Use this command to configure the V.44 data compression method used by
the modem. The soft modem never disconnect if V.44 is not negotiated and
always use the streaming method for data transfers.
As a result, <compression_negotiation> and <capability> are always 0.
The <direction> parameter sets which directions use the compression method.
The soft modem use compression in one or both directions.
Valid <direction> Values:
0
Modem negotiates no V.44 compression.
1
Modem negotiates transmit only V.44 compression.
2
Modem negotiates receive only V.44 decompression.
3
Modem accepts compression in both or either direction
(default).
The <max_codewords_tx> parameter specifies the maximum number of code
words to negotiate in the transmit direction. The <max_codewords_rx>
parameter specifies the maximum number of code words to negotiate in the
receive direction.
Valid <max_codewords_tx> and <max_codewords_rx> Values:
2048
Default <max_codewords_tx> and
<max_codewords_rx> value.
512, 1024, 2048
Valid transmit and receive code word settings.
The <max_string_tx> parameter specifies the maximum string length to
negotiate in the transmit direction. The <max_string_rx> parameter specifies
the maximum string length to negotiate in the receive direction.
Valid <max_string_tx> and <max_string_rx> Values:
255
Default <max_string_tx> and <max_string_rx> value.
32—255
Valid transmit and receive string lengths.
The <max_history_tx> parameter specifies the maximum length of the
history buffer to negotiate in the transmit direction. The <max_history_rx>
parameter specifies the maximum length of the history buffer to negotiate in
the receive direction.
Valid <max_history_tx> and <max_history_rx> Values:
6144
Default <max_history_tx> and
<max_history_rx> value.
1024, 2048, 4096, 1536, 3072, 6144
Valid maximum transmit and receive
history buffer sizes.
