V.92 and V.44 Commands

Every command in this table must begin with the AT prefix and be executed by pressing ENTER.

Example:AT+PCW?<ENTER> displays the current setting for call waiting.

Command Function Default Options
+DCS=n Selects data compression algorithm. 1,1 This is a compound parameter. The full syntax is as follows:

+DCS=<v42bis>,<v44>

Valid values for <v42 bis>
Value Meaning
0 Disables V.42 bis.
1 Enables V.42 bis.

Valid values for <v44>
Value Meaning
0 Disables V.44.
1 Enables V.44.
2 Enables V.44 for V.92 servers only.

+DS44 Configures the V.44 data compression method. None. This is a compound parameter. The full syntax is as follows:

+DS44=<direction>,<compression_negotiation>,<compatibility>,<max_codewords_tx>,<max_codewords_rx>,<max_string_tx>,<max_string_rx>,<max_history_tx>,<max_history_rx>

Valid values for <direction>
Value Meaning
0 Do not negotiate V.44 compression.
3 Accept V.44 compression in both directions.

Valid values for <max_codewords_tx> and <max_codewords_rx>
Value Meaning
1024 Default.
256–2048 Valid transmit and receive code word settings.

Valid values for <max_string_tx> and <max_string_rx>
Value Meaning
255 Default.
31–255 Valid transmit and receive string lengths.
+PCW=n Controls Call Waiting. +PCW=2 0 Enables the Call Waiting detector. When a Call Waiting signal is detected, the modem toggles the Ring Indicator and displays the Caller ID.
1 Enables the Call Waiting detector. When a Call Waiting signal is detected, the modem hangs up the current call.
2 Disables the Call Waiting detector.
? Displays a list of valid +PCW settings.
+PCW? Displays the current +PCW setting. None. None.
+PIG=n Controls PCM (Pulse Code Modulation). +PIG=0 0 Enables PCM upstream.
1 Disables PCM upstream.
? Displays a list of valid +PIG settings.
+PIG? Displays the current +PIG setting. None. None.
+PMH=n Controls Modem-On-Hold. +PHM=0 0 Enables Modem-On-Hold.
1 Disables Modem-On-Hold.
? Displays a list of valid +PMH settings.
+PMHDn Switches the line while Modem-On-Hold is active. None.

0–9, #, and *.

Dials the characters in the dial string specified by n.
+PMHF Generates a hook flash during Modem-On-Hold operations. None. None.
+PMHR Initiates a Modem-On-Hold Request. None. None.
+PMHT=n Controls the Modem-On-Hold timer. +PMHT=0 0 Denies Modem-On-Hold request.
? Displays a list of valid +PMHT settings.
+PMHT? Displays the current +PMHT setting. None. None.
+PQC=n Configures the Quick Connect sequence.

After configuring the sequence, use +PSS to enable or disable Quick Connect.

 +PCQ=0 0 Enables phases 1 and 2.
1 Enables phase 1; disables phase 2.
3 Disables phases 1 and 2.
? Displays a list of valid +PQC settings.
+PQC? Displays the current +PQCT setting. None. None.
+PSS=n Enables or disables Quick Connect. +PSS=0 0 Allows Normal or Quick Connect if enabled by +PQC.
1 Allows Quick Connect only if enabled by +PQC. Otherwise, disconnects.
2 Disables phases 1 and 2 independently of +PQC.
? Displays a list of valid +PSS settings.
+PSS? Displays the current +PSS setting. None. None.

V.80 Commands

Every command in this table must begin with the AT prefix and be executed by pressing ENTER.

Example:AT+A8E?<ENTER> displays the current settings for V.8 or V.8 bis negotiation.

Command Function Default Options
+A8E=n Sets V.8 operation. +A8E=1,1,,1 This is a compound parameter. The full syntax is as follows:

+A8E=<v8o>,<v8a>,<v8cf>,<v8b>

Valid values for <v8o>
Value Meaning
1 Enables DCE-controlled V.8 origination negotiation.
6 Enables DCE-controlled V.8 origination negotiation, issue +A8x indications.

Valid values for <v8a>
Value Meaning
1 Enable DCE-controlled V.8 answer negotiation.
5 Disable DCE-controlled V.8 answer negotiation, issue +A8x indications.

Valid values for <v8cf>
Value Meaning
0-FF
Sets the V.8 CI signal call function to the value specified.
0xC1 Default value

Valid values for <v8b>
Value Meaning
0 Disable V.8 negotiation.
1 Enable DCE-controlled V.8bis negotiation.
2 Enable DTE-controlled V.8 negotiation.
? Displays a list of valid +A8E settings.
+A8E? Display the current settings for V.8 or V.8 bis negotiation. None. None.
+A8T=n Sends a V.8 bis signal or message from the local DCE when V.80 is enabled None. This is a compound parameter. The full syntax is as follows:

+A8T=<signal>,<1st message>,<2nd message>,<sig en>,<msg en>,<supp delay >

Valid values for <signal>
Value Meaning
0 None.
1 Initiating Mre.
2 Initiating MRd.
3 Initiating CRe, low power.
4 Initiating CRe, high power.
5 Initiating CRd.
6 Initiating Esi.
7 Responding MRd, low power.
8 Responding MRd, high power.
9 Responding CRd.
10 Responding Esr.

Valid values for <sig_en>
Value Meaning
0 Enable detection of initiation signals (default).
1 Enable detection of responding signals .

Valid values for <msg_en>
Value Meaning
0 Enable detection of messages (default).
1 Enable detection of V.8 bis messages.

Valid values for <supp_delay>
Value Meaning
0 No delay inserted (default).
1 Insert 1.5 second delay between transmitted V.8 bis signal and the subsequent V.8 bis message.
? Displays a list of valid +A8T settings.
+A8T? Displays the current +A8T setting. None. None.
+IFC=n Selects the local flow control method. +IFC=2,2 0,0 No flow control.
1,1 Software flow control.
2,2 Hardware flow control.
? Displays a list of valid local flow control settings.
+IFC? Displays the current local flow control setting. None. None.
+ITF=n Sets the transmit flow control thresholds. None. off The signal threshold, in octets, above which the DCE will generate a flow-off signal.
on The signal threshold, in octets, below which the DCE will generate a flow-on signal.
? Displays a list of valid +IFC settings.
+ITF? Displays the current transmit flow control setting. None. None.