HAYES MODEM AT COMMANDS

AT MODEM COMMANDS
COMMAND ACTION
A Enters answer mode. After going off hook, the modem will answer the incoming call. It will then go on-line with the other modem.
A/ Previous command line is repeated. Not to be preceded by AT nor followed by
B0 Use CCITT V.22 at 1200 bps
B1 Use 212A at 1200 bps. Not supported in the United Kingdom
B2 When making a call using CCITT V.23, transmit at 75 bps and receive at 1200 bps. When answering and N0, transmit at 1200 bps and receive at 75 bps.
B3 When making a call using V.23, transmit at 1200 bps and receive at 75 bps. When answering and N0 selected, transmit at 75 bps and receive at 1200 bps.
B15 Use CCITT V.21 at 300 bps
B16 Use 103 at 300 bps. Not supported in the United Kingdom.
B41 Use CCITT V.32 at 4800 bps
B42 Use Express 96 at 4800 bps
B60 Use CCITT V.32 at 9600 bps
B61 Use Hayes Express 96 proprietray protocol 9600 bps connection.
D Originate mode. The modem goes off-hook and tries to go on-line with another modem. The dial modifiers (see next table) direct the modem what, when, and how to dial.
E0 In command state, characters are not echoed from the keyboard to the screen.
E1 In command state, characters are echoed from the keyboard to the screen
H0 After hanging up, place modem in command state.
H1 After going off hook, operate auxilary relay
I0 Show numeric product code
I1 ROM checksum is calculated
I2 ROM checksum is verified (output is OK or ERROR)
L0, L1 Speaker volume low
L2 Speaker volume medium
L3 Speaker volume high
M0 Speaker off
M1 Speaker on until carrier detected
M2 Speaker on
M3 Except when dialing, speaker on until carrier detected
N0 Handshake only at rate specified by S37 while originating or answering
N1 Negotiate common communication standard, while originating, at the optimum line speed supported by both modems. Negotiations start at the DCE line speed specified in S37, dropping back to a slower speed if required. Go back from CCITT V.22 to CCITT V.21, when answering.
N2 Negotiate common communication standard, while originating, at the optimum line speed supported by both modems. Negotiations start at the DCE line speed specified in S37, dropping back to a slower speed if required. Go back from CCITT V.22 to CCITT V.23/CCITT V.21, when answering.
N3 Handshake only at speed defined by S37, when originating. Go back from CCITT V.32 to CCITT V.22./212A/CCITT V.22bis, finally 103, when answering
N4 Handshake only at speed defined by S37, when originating. Go back from CCITT V.32 to CCITT V.22./212A/CCITT V.22bis, finally 103, when answering
N5 Negotiate common communication standard, while originating, at the optimum line speed supported by both modems. Negotiations start at the DCE line speed specified in S37, dropping back to a slower speed if required. Handshake only at speed defined by S37, when answering.
O0 Enter on-line state
O1 Enter on-line state. Then start equlaizer retrain sequence
O3 Enter on-line state. Then start CCITT V.32bis rate renogotiation sequence
Q0 Result codes are returned
Q1 Result codes are not returned
Q2 Result codes are retruned in originate mode. Result codes are not returned in answer mode
Sr? Read and respond with current value of register r. ? requests the value assigned to that register.
Sr=n Register r is set to n.
V0 Result codes are shown as numbers
V1 Result codes are shown as words
W0 Negotiation progress messages are not returned
W1 Negotiiation progress messages are returned
W2 Negotiation progress messages are not returned. CONNECT messages are returned with modem-to-modem (DCE) speeds, not modem-to-DTE speeds.
X0 Give basic call progress result codes: CONNECT , NO CARRIER ,and RING
X1 Give basic call progress result codes and connection speeds (for example, CONNECT 2400)
X2 Give basic call progress result codes, connection speed, and DIALTONE detection
X3 Give basic call progress result codes, connection speed and BUSY signal detection
X4 Give basic call progress result codes connection speed, BUSY signal detection and DIALTONE detection.
Y0 Ignore longspace disconnect
Y1 Obey longspace disconnect
Z0 After reset, recall user profile 0
Z1 After reset, recall user profile 1
&A0 When auto-answering, connect as answering modem
&A1 When auto-answering, connect as originating mode,
&C0 Presence of carrier detect signal is assumed (ROM default. This value is recalled after &F is issued)
&C1 Track status of carrier detect signal
&C2 Presence of carrier detect signal is assumed until on-line. From that point, track status of signal
&D0 Status of DTR signal is ignored. (ROM Default. This value is recalled after &F is issued)
&D1 DTR signal is monitored. The modem enters command state after an on-to-off transition of DTR signal. If the connection is intact, the O0 command returns to the on-line state.
&D2 DTR signal is monitored. The modem hangs up and enters command state after an on-to-off transition of DTR signal.
&D3 DTR signal is monitored. The modem hangs up and resets after an on-to-off transition of DTR signal.
&F Recall factory configuration
&G0 Guard tones not used (Not supported in Netherlands, Norway, Sweden, Switzerland, or the United Kingdom)
&G2 1800 Hz Guard tones are used
&J0 Configure for RJ-11, RJ-41S, RJ-45S telco jacks
&J1 Configure for RJ-12, RJ-13 telco jacks (Not supported in Netherlands, Norway, Sweden, Switzerland, or the United Kingdom)
&K0 Local flow control disabled
&K1 RTS/CTS local flow control enabled
&K2 XON/XOFF local flow control enabled
&K3 RTS/CTS local flow control enabled
&K4 XON/XOFF local flow control enabled
&K5 Transparent XON/XOFF local flow control enabled
&L0 Set for dial-up mode
&L1 Set modem for conditioned leased line (private speechband circuit) mode
&On Go to the X.25 PAD command state of channel n(n=0-3) from the AT command state. The modem will return to the command state of last channel selected, if a parameter for this command is not specified.
&Q0 Communicate in asynchronous mode
&Q1 Communicate is asynchronous mode 1 - Async-to-Sync
&Q2 Communicate in asynchronous mode 2 - Stored Number Dial
&Q3 Communicate in asynchronous mode 3 - Voice/Data Switch
&Q4 Communicate in asynchronous mode 4 - Hayes AutoSync.
&Q5 Communicate in error-control mode
&Q6 For interfaces requiring constant speed between the DTE (computer/terminal) and the DCE (modem), communicate in asynchronous mode with automatic speed buffering (ASB)
&R0 Track CTS according to RTS
&R1 Assume CTS (ignore RTS)
&S0 Assert DSR signal always
&S1 Assert DSR signal before handshake only
&S2 After handshake negotiation, assert DSR signal, but before CONNECT XXXXX result code is sent to the DTE
&T0 Halt any test in progress
&T1 Start local analog loopback
&T3 Start local digital loopback
&T4 Grant request from remote modem for remote digital loopback
&T5 Deny request from remote modem for remote digital loopback
&T6 Start remote digital loopback
&T7 Start remote digital loopback with self-test
&T8 Start local analog loopback with self-test
&T19 Find out if RTS and CTS circuits are supported in the DTE cable
&U0 Trellis coding enabled (CCITT V.32 9600 bps only)
&U1 Trellis coding disabled
&V View active, user profiles, and stored telephone numbers
&W0 Write current configuration parameters in memory as profile 0
&W1 Write current configuration parameters in memory as profile 1
&X0 Derive transmit clock signal from modem's internal oscillator (internal clock signal on pin 15)
&X1 Derive transmit clock signal from attached computer (external clock signal on pin 24)
&X2 Derive transmit clock signal from receive carrier (slave receive clock signal on pin 15)
&Y0 Set stored user profile 0 as power-up configuration
&Y1 Set stored user profile 1 as power-up configuration
&Zn=x Store phone number x in location n (n=0-3)
Note: The modem must be configured for &Q0(unbuffered asynchronous mode) for the &T commands to be entered. For &T19 to work, it must be supported by the terminal software. Note: &Q0unbuffered asynchronous mode &T &T19

COMMAND	ACTION
A	Enters answer mode. After going off hook, the modem will answer the incoming call. It will then go on-line with the other modem.
A/	Previous command line is repeated. Not to be preceded by AT nor followed by
B0	Use CCITT V.22 at 1200 bps
B1	Use 212A at 1200 bps. Not supported in the United Kingdom
B2	When making a call using CCITT V.23, transmit at 75 bps and receive at 1200 bps. When answering and N0, transmit at 1200 bps and receive at 75 bps.
B3	When making a call using V.23, transmit at 1200 bps and receive at 75 bps. When answering and N0 selected, transmit at 75 bps and receive at 1200 bps.
B15	Use CCITT V.21 at 300 bps
B16	Use 103 at 300 bps. Not supported in the United Kingdom.
B41	Use CCITT V.32 at 4800 bps
B42	Use Express 96 at 4800 bps
B60	Use CCITT V.32 at 9600 bps
B61	Use Hayes Express 96 proprietray protocol 9600 bps connection.
D	Originate mode. The modem goes off-hook and tries to go on-line with another modem. The dial modifiers (see next table) direct the modem what, when, and how to dial.
E0	In command state, characters are not echoed from the keyboard to the screen.
E1	In command state, characters are echoed from the keyboard to the screen
H0	After hanging up, place modem in command state.
H1	After going off hook, operate auxilary relay
I0	Show numeric product code
I1	ROM checksum is calculated
I2	ROM checksum is verified (output is OK or ERROR)
L0, L1	Speaker volume low
L2	Speaker volume medium
L3	Speaker volume high
M0	Speaker off
M1	Speaker on until carrier detected
M2	Speaker on
M3	Except when dialing, speaker on until carrier detected
N0	Handshake only at rate specified by S37 while originating or answering
N1	Negotiate common communication standard, while originating, at the optimum line speed supported by both modems. Negotiations start at the DCE line speed specified in S37, dropping back to a slower speed if required. Go back from CCITT V.22 to CCITT V.21, when answering.
N2	Negotiate common communication standard, while originating, at the optimum line speed supported by both modems. Negotiations start at the DCE line speed specified in S37, dropping back to a slower speed if required. Go back from CCITT V.22 to CCITT V.23/CCITT V.21, when answering.
N3	Handshake only at speed defined by S37, when originating. Go back from CCITT V.32 to CCITT V.22./212A/CCITT V.22bis, finally 103, when answering
N4	Handshake only at speed defined by S37, when originating. Go back from CCITT V.32 to CCITT V.22./212A/CCITT V.22bis, finally 103, when answering
N5	Negotiate common communication standard, while originating, at the optimum line speed supported by both modems. Negotiations start at the DCE line speed specified in S37, dropping back to a slower speed if required. Handshake only at speed defined by S37, when answering.
O0	Enter on-line state
O1	Enter on-line state. Then start equlaizer retrain sequence
O3	Enter on-line state. Then start CCITT V.32bis rate renogotiation sequence
Q0	Result codes are returned
Q1	Result codes are not returned
Q2	Result codes are retruned in originate mode. Result codes are not returned in answer mode
Sr?	Read and respond with current value of register r. ? requests the value assigned to that register.
Sr=n	Register r is set to n.
V0	Result codes are shown as numbers
V1	Result codes are shown as words
W0	Negotiation progress messages are not returned
W1	Negotiiation progress messages are returned
W2	Negotiation progress messages are not returned. CONNECT messages are returned with modem-to-modem (DCE) speeds, not modem-to-DTE speeds.
X0	Give basic call progress result codes: CONNECT , NO CARRIER ,and RING
X1	Give basic call progress result codes and connection speeds (for example, CONNECT 2400)
X2	Give basic call progress result codes, connection speed, and DIALTONE detection
X3	Give basic call progress result codes, connection speed and BUSY signal detection
X4	Give basic call progress result codes connection speed, BUSY signal detection and DIALTONE detection.
Y0	Ignore longspace disconnect
Y1	Obey longspace disconnect
Z0	After reset, recall user profile 0
Z1	After reset, recall user profile 1
&A0	When auto-answering, connect as answering modem
&A1	When auto-answering, connect as originating mode,
&C0	Presence of carrier detect signal is assumed (ROM default. This value is recalled after &F is issued)
&C1	Track status of carrier detect signal
&C2	Presence of carrier detect signal is assumed until on-line. From that point, track status of signal
&D0	Status of DTR signal is ignored. (ROM Default. This value is recalled after &F is issued)
&D1	DTR signal is monitored. The modem enters command state after an on-to-off transition of DTR signal. If the connection is intact, the O0 command returns to the on-line state.
&D2	DTR signal is monitored. The modem hangs up and enters command state after an on-to-off transition of DTR signal.
&D3	DTR signal is monitored. The modem hangs up and resets after an on-to-off transition of DTR signal.
&F	Recall factory configuration
&G0	Guard tones not used (Not supported in Netherlands, Norway, Sweden, Switzerland, or the United Kingdom)
&G2	1800 Hz Guard tones are used
&J0	Configure for RJ-11, RJ-41S, RJ-45S telco jacks
&J1	Configure for RJ-12, RJ-13 telco jacks (Not supported in Netherlands, Norway, Sweden, Switzerland, or the United Kingdom)
&K0	Local flow control disabled
&K1	RTS/CTS local flow control enabled
&K2	XON/XOFF local flow control enabled
&K3	RTS/CTS local flow control enabled
&K4	XON/XOFF local flow control enabled
&K5	Transparent XON/XOFF local flow control enabled
&L0	Set for dial-up mode
&L1	Set modem for conditioned leased line (private speechband circuit) mode
&On	Go to the X.25 PAD command state of channel n(n=0-3) from the AT command state. The modem will return to the command state of last channel selected, if a parameter for this command is not specified.
&Q0	Communicate in asynchronous mode
&Q1	Communicate is asynchronous mode 1 - Async-to-Sync
&Q2	Communicate in asynchronous mode 2 - Stored Number Dial
&Q3	Communicate in asynchronous mode 3 - Voice/Data Switch
&Q4	Communicate in asynchronous mode 4 - Hayes AutoSync.
&Q5	Communicate in error-control mode
&Q6	For interfaces requiring constant speed between the DTE (computer/terminal) and the DCE (modem), communicate in asynchronous mode with automatic speed buffering (ASB)
&R0	Track CTS according to RTS
&R1	Assume CTS (ignore RTS)
&S0	Assert DSR signal always
&S1	Assert DSR signal before handshake only
&S2	After handshake negotiation, assert DSR signal, but before CONNECT XXXXX result code is sent to the DTE
&T0	Halt any test in progress
&T1	Start local analog loopback
&T3	Start local digital loopback
&T4	Grant request from remote modem for remote digital loopback
&T5	Deny request from remote modem for remote digital loopback
&T6	Start remote digital loopback
&T7	Start remote digital loopback with self-test
&T8	Start local analog loopback with self-test
&T19	Find out if RTS and CTS circuits are supported in the DTE cable
&U0	Trellis coding enabled (CCITT V.32 9600 bps only)
&U1	Trellis coding disabled
&V	View active, user profiles, and stored telephone numbers
&W0	Write current configuration parameters in memory as profile 0
&W1	Write current configuration parameters in memory as profile 1
&X0	Derive transmit clock signal from modem's internal oscillator (internal clock signal on pin 15)
&X1	Derive transmit clock signal from attached computer (external clock signal on pin 24)
&X2	Derive transmit clock signal from receive carrier (slave receive clock signal on pin 15)
&Y0	Set stored user profile 0 as power-up configuration
&Y1	Set stored user profile 1 as power-up configuration
&Zn=x	Store phone number x in location n (n=0-3)