AT Command set summary for PCTel chipset
 

Table 1. AT Command Set
Command
Function
AT Attention - this precedes all commands except A/
A/ 
Execute previous command - does not require a <CR> * 
A
Causes the modem to go off hook. If a call is coming in, the modem will try to answer it. The procedure for answering a call is a short silence and then an answer tone. Sending a character to the modem during this procedure will abort the answer procedure. The amount of time the modem will wait for a carrier is programmable by modifying the S7 register. 
B0
B1
B2
B0 Select CCITT V.22 (1200 bps)
Select Bell 212A (1200 bps)
Select CCITT V23 Originate mode will transmit data at 75 bps and receive data at 1200 bps. Answer mode will transmit data at 1200bps and receive data at 75bps. The command N0 (Disable auto mode) must be selected. 
D
Dmn
D alone will take the modem off-hook and wait for a dial tone. (See X command for exceptions) The length of time to wait for a dialtone before dialing is programmable in register S6.
ATDmn will dial a phone number where m is a modifier: L, W, ,, ;, @, !, or S. It will dial the telephone number n.
L
Dial last number 
W
Wait for dial tone. If you have selected X0 or X1 (disable dial tone detection), then you can use this modifier to override that setting.
,
Pause during dial. The amount of time to pause is determined in register S8.
;
Return to command mode after dialing. It doesn't wait for carrier or hang up. 
@
Wait for 5 seconds of silence. This is used to access systems that do not provide a dial tone.
!
Hook flash. Causes the modem to go on-hook for 0.5 seconds. This is used in PBX systems and for voice features like call waiting
S=(0-9)
Dials a stored number. Up to ten numbers can be stored, and the addresses are from 0 to 9. To store a number into one of these addresses, use the &Z command.
^
Turns on 1300Hz calling tone.
E0
E1
Commands issued to the modem are not echoed to the local terminal. This only matters in the command mode. It does not affect the modems ability to send response codes.
Commands are echoed to the local terminal.
H0
H1
Force modem on-hook (hang-up).
Force modem off-hook (to answer or dial).
I0
I1
I2
I3
I4
Return numeric product code
Return hardware variation code
Report internal code
Report software revision number
Report product feature listing
L0
L1
L2
L3
Speaker volume zero
Speaker volume low
Speaker volume low
Speaker volume low (Hardware currently limits volume adjustment to on/off) 
M0
M1
M2
M3
Speaker always off
Speaker on until carrier detected
Speaker always on
Speaker on during answering only
N0
N1
Disable auto-mode. This forces the modem to connect at the speed specified in register S37.
Enable auto-mode. The modem will answer at the highest available line speed and ignore any ATBn command.
O0
O1
Return to data mode. If you have entered the command mode using the time independent escape sequence, this will put you back in data mode without going on-hook.
Retrain the modem. If the line condition has changed since the original connection, retraining the modem will cause it to reconnect at the most efficient speed for the current line condition.
P
Pulse dialing allows the modem to work on telephone networks where tone is not supported.
Q0
Q1
Enable response to DTE.
Disable response to DTE. The modem does not respond to the terminal. Issuing a command will not produce a response (unless the command is something like ATZ, which will restore this setting to default.)
Sn 
Set default S-register. Any subsequent = or ? commands will modify the default S register. 
Sn=m
Set register n to value m
Sn?
Return the value of register n
T
Tone dialing
V0
V1
Result codes will be sent in numeric form. (See the result code table 3)
Result codes will be sent in word form. (See the result code table 3). 
W0
W1
W2
Report DTE speed only. After connection, there will be no message about what Error Correction or Data Compression protocol is in use.
Report DCE speed, Error Correction/Data Compression protocol, and DTE speed.
Report DCE speed only
X0
X1
X2
X3
X4
Send OK, CONNECT, RING, NO CARRIER, ERROR and NO ANSWER. Busy and Dial Tone Detection are disabled. 
Send X0 messages and CONNECT speed
Send X1 message and NO DIALTONE
Send X2 messages except NO DIALTONE, BUSY and RING BACK
Send all responses
Y0
Y1
Disable long space disconnect
Enable long space disconnect; with error correction, hang up after sending 1.6 second long space; without error correction, hang up after 4 second long space.
Z0
Z1
Reset modem to profile 0 
Reset modem to profile 1 
=n
Sets the value of the default S register
?
Reports the value stored in the default S register.

 

Table 1. & Ampersand Commands
Command
Function
&C0
&C1
Force DCD on
DCD follows remote carrier
&D0
&D1
&D2
&D3
DTR is assumed on
DTR drop causes modem back to command mode without disconnecting
DTR drop causes modem to hang up
DTR drop causes modem to be initialized;&Y determines which profile is loaded.
&F
Load factory profile
&G0
&G1
&G2
Disable guard tone
Enable 550Hz guard tone
Enable 1800Hz guard tone on answering modem
&K0
&K3
&K4
&K5
&K6
Disable flow control
Enable RTS/CTS flow control
Enable XON/XOFF flow control
Enable transparent software flow control
Enable both RTS/CTS and XON/XOFF flow control
&P0
&P1
Make/break pulse dial ratio of 39/61
Make/break pulse dial ratio of 33/67
&S0
&S1
Force DSR on
DSR on at the start of handshaking and off after carrier loss
&T0
&T1
Terminate test
Start ALB test
&U0
&U1
Enable trellis coding
Disable trellis coding
&V0
&V1
&V2
Display active profile
Display stored profiles
Display stored telephone numbers 
&W0
&W1
Save active profile to profile 0
Save active profile to profile 1
&Y0
&Y1
Use profile 0 on powerup
Use profile 1 on powerup
&Zn=m
Save telephone number (up to 36 digits) into memory location n (0-9)

 

Table 1. % Percent Commands
Command
Function
%C0
%C1
%C2
%C3
Disable data compression 
Enable MNP5 compression
Enable V.42bis compression
Enable both V.42bis and MNP5
%E0
%E1
%E2
%E3
Disable auto-retrain
Enable auto-retrain
Enable auto-retrain and fallback
Enable auto-retrain and fast hang up
%L
Report received signal level in -dBm
%N0
%N1
%N2
%N3
%N4
%N5
%N6
%N7
%N8
%N9
Dynamic CPU loading disabled
Dynamic CPU loading not to exceed 10%
Dynamic CPU loading not to exceed 20%
Dynamic CPU loading not to exceed 30%
Dynamic CPU loading not to exceed 40%
Dynamic CPU loading not to exceed 50%
Dynamic CPU loading not to exceed 60%
Dynamic CPU loading not to exceed 70%
Dynamic CPU loading not to exceed 80%
Dynamic CPU loading not to exceed 90%
%Q
Report line signal quality

 

Table 1. \ Backslash Commands
Command
Function
\A0
\A1
\A2
\A3
64-character max. MNP block size
128-character max. MNP block size
192-character max. MNP block size 
256-character max. MNP block size 
\Bn
In non-error correction mode, transmit break in 100 ms units (1-9 with default 3)
\G0
\G1
Disable XON/XOFF flow control (modem to modem)
Enable XON/XOFF flow control (modem to modem)
\Kn
Define break type (refer to table 2)
\L0
\L1
Use stream mode for MNP
Use interactive block mode for MNP
\N0
\N1
\N2
\N3
\N4
\N5
Normal mode; speed control without error correction
Plain mode; no speed control and no error correction
Reliable mode
Auto-reliable mode
LAPM error correction only
MNP error correction only

 

Table 1. * Asterisk Commands
Command
Function
*Q0
*Q1
Send the "CONNECT xxxx" result codes to the DTE when an invalid TIES escape sequence is detected after the "OK" response has already been sent
Does NOT send the "CONNECT xxxx" result codes to the DTE when an invalid TIES escape sequence is detected after the "OK" response has already been sent

 

Table 2. Break Types
Command
Function
\Kn
\K0
\K1
\K2
\K3
\K4
\K5
Local DTE sends break during normal or reliable mode
Enter command state; no break to remote
Empty data buffers; break to remote
Same as \K0
Immediately send break to remote
Same as \K0
Send break to remote with TXD data
\Kn
\K0
\K1
\K2
\K3
\K4
\K5
Local modem sends break during plain mode
Break to remote; and enter command state
Same as \K0
Send break to remote
Same as \K0
Same as \K2
Same as \K2
\Kn
\K0
\K1
\K2
\K3
\K4
\K5
Remote modem sends break during normal mode
Empty data buffers; and send break to DTE
Same as \K0
Immediately send break to DTE
Same as \K2
Send break to DTE with buffered RXD data
Same as \K4

 

Table 3. Result Codes
Long Form
Short Form
Description
OK
0
Modem successfully executed a AT command
CONNECT
1
A connection established
RING
2
Modem detected an incoming call
NO CARRIER
3
Modem lost or could not detect a remote carrier signal within the register S7 time 
ERROR
4
Modem detected an error in an AT command
CONNECT 1200
5
Connection at 1200 bps
NO DIALTONE
6
Modem did not detect a dial tone within 5 seconds after off-hook
BUSY
7
Modem detected a busy tone
NO ANSWER
8
Modem did not detect 5 seconds of silence when using the @ dial modifier in the dial command
CONNECT 0600
9
Connection at 600 bps
CONNECT 2400
10
Connection at 2400 bps
CONNECT 4800
11
Connection at 4800 bps
CONNECT 9600
12
Connection at 9600 bps
CONNECT 7200
13
Connection at 7200 bps
CONNECT 12000
14
Connection at 12000 bps
CONNECT 14400
15
Connection at 14400 bps
CONNECT 19200
16
Connection at 19200 bps
CONNECT 38400
17
Connection at 38400 bps
CONNECT 57600
18
Connection at 57600 bps
CONNECT 115200 
19
Connection at 115200 bps
CONNECT 28800
20
Connection at 28800 bps
CONNECT 300
21
Connection at 300 bps
CONNECT 1200TX/75RX
22
Connection at transmit 1200/receive 75 bps
CONNECT 75TX/1200RX
23
Connection at transmit 75/receive 1200 bps
CONNECT 110
24
Connection at 110 bps
RING BACK
25
Ring Back signal detected
+FCERROR
+F4
Error occured in Class 1 fax operation
FAX
33
Fax modem connection established
DATA
35
Data modem connection established
CARRIER 300
40
Carrier rate of 300 bps
CARRIER 1200/75
44
Carrier rate of transmit 1200/receive 75 bps
CARRIER 75/1200
45
Carrier rate of transmit 75/receive 1200 bps
CARRIER 1200
46
Carrier rate of 1200 bps
CARRIER 2400
47
Carrier rate of 2400 bps
CARRIER 4800
48
Carrier rate of 4800 bps
CARRIER 7200
49
Carrier rate of 7200 bps
CARRIER 9600
50
Carrier rate of 9600 bps
CARRIER 12000
51
Carrier rate of 12000 bps
CARRIER 14400
52
Carrier rate of 14400 bps
CARRIER 16800
53
Carrier rate of 16800 bps
CARRIER 19200
54
Carrier rate of 19200 bps
CARRIER 21600
55
Carrier rate of 21600 bps
CARRIER 24000
56
Carrier rate of 24000 bps
CARRIER 26400
57
Carrier rate of 26400 bps
CARRIER 28800
58
Carrier rate of 28800 bps
CONNECT 16800
59
Connection at 16800 bps
CONNECT 21600
61
Connection at 21600 bps
CONNECT 24000
62
Connection at 24000 bps
CONNECT 26400
63
Connection at 26400 bps
COMPRESSION: CLASS 5
66
MNP Class 5 data compression connection established 
COMPRESSION: V.42bis
67
V.42bis data compression connection established
COMPRESSION: NONE
69
Connection established without data compression
PROTOCOL: NONE
76
Connection established without error correction
PROTOCOL: LAPM
77
V.42/LAPM error correction connection established
PROTOCOL: ALT
 80 MNP 3-4 error correction connection established

 

Table 4. S-Registers
Register
Function
0
Rings to auto-answer
Set the number of rings required before the modem answers. 0 setting disables auto-answer.
Range: 0 - 255 rings
Default: 0 (auto-answer disabled)
1
Ring counter
Count the number of rings before the modem answers.
Range: 0 - 255 rings
Default: 0 
2
Escape character
Define the character used for the three-character escape code sequence. 0 setting disables the escape code character.
Range: 0 - 127
Default: 43 (+)
3
Carriage return character
Define the character for carriage return
Range: 0 - 127
Default: 13 (carriage return)
4
Line feed character
Define the character for line feed 
Range: 0 - 127 
Default: 10 (line feed) 
5
Backspace character
Define the character for backspace
Range: 0 - 127
Default: 8 (backspace)
6
Wait before dialing
Set the length of time to pause after off hook before dial.
Range: 2 - 255 seconds
Default: 2 seconds
7
Wait for carrier after dial
Set the length of time that the modem waits for a carrier from the remote modem before hanging up.
Range: 1 - 255 seconds
Default: 50 seconds
8
Pause time for dial delay
Set the length of time to pause for the pause dial modifier ",".
Range: 0 - 255 seconds
Default: 2 seconds
9
Carrier detect response time
Define the length of time a signal is detected and qualified as a carrier.
Range: 1 - 255 tenths of a second
Default: 6 (0.6 second)
10
Lost carrier hang up delay
Set the length of time the modem waits before hanging up for a carrier loss.
Range: 1 - 255 tenths of a second
Default: 14 (6 seconds)
11
DTMF speed control
Set the length of tone and the time between tones for the tone dialing.
Range: 50 - 255 milliseconds
Default: 95 milliseconds
12
Escape Prompt Delay (EPD) timer
Set the time from detection of the last character of the three character escape sequence until the "OK" is returned to the DTE
Range: 0 - 255 fiftieths of a second
Default: 50 (1 second)
13
Reserved
14
Reserved
15
Reserved
16
Reserved
17
Reserved
18
Test timer
Set the length of loopback test.
Range: 0 - 255 seconds
Default: 0 (disable timer)
19
Reserved
20
Reserved
21
Reserved
22
Reserved
23
Reserved
24
Reserved
25
Delay to DTR
Set the length of time the modem ignores DTR before hanging up
Range: 0 - 255 hundredths of a second
Default: 5 (0.05 second)
26
Reserved
27
Reserved
28
Reserved
30
Disconnect inactivity timer
set the length of time allowed for inactivity before the connection is hung up.
Range: 0-255 in 10 seconds
Default: 0 (disabled)
32
XON character
Set the value of XON character
Range: 0-255
Default: 17
33
XOFF character
Set the value of XOFF character
Range: 0-255
Default: 19
34
V.34 data rate (bit-rate)
Set the maximum bit rate for V.34
Range : 0-8 (2400 baud)
1-10 (3000 baud)
1-11 (3200 baud)
1-13 (3429 baud) bit rate = ((S34)+1) * 2400bps 
Default: 13 (33600 bps) 
35
V.34 symbol rate (baud-rate)
Set the maximum baud rate for V.34
Range: 0-5
0 - 2400 baud
1 - 2743 baud (N/A)
2 - 2800 baud (N/A)
3 - 3000 baud 
4 - 3200 baud 
5 - 3429 baud (N/A until V.34bis) 
Default: 0 (2400 baud)
36
Reserved
37
Line connection speed
0 - Attempt to connect at the highest speed
3 - Attempt to connect at 300 bps
4 - Attempt to connect at 1200 bps
6 - Attempt to connect at 2400 bps
7 - Attempt to connect at 4800 bps
8 - Attempt to connect at 7200 bps
9 - Attempt to connect at 9600 bps
10 - Attempt to connect at 12000 bps
11 - Attempt to connect at 14400 bps
12 - Attempt to connect at V.34
Default: 0
38
Delay before forced hang up
Set the delay to hang up after the disconnecting command is received.
Range: 0 - 255 seconds
Default: 20 seconds
39
Reserved
40
Reserved
41
Reserved
42
Reserved
43
Reserved
44
Reserved
45
Reserved
46
Reserved
47
Reserved
48
Reserved
82
Reserved
86
Call failure reason code
0 - Normal disconnect; no error 
4 - Loss of carrier 
5 - V.42 negotiation failed to detect an error correction modem at remote end 
6 - No response to complete negotiation 
9 - No common protocol 
12 - Remote initiated a normal disconnect 
13 - Remote modem did not respond after 10 message retransmissions 
14 - Protocol violation 
15 - Compression Failure 
20 - Hang up by inactivity time out 
91
Transmit level
Set the transmit level in -dBm
Range: 0 - 15 (-dBm)
Default: 11 (-11 dBm)

 

Table 6. FAX Class 1 Command Set
Command
Function
+FCLASS=0
+FCLASS=1
+FCLASS=?
Select data mode
Select facsimile Class 1 mode
Report service classes supported
+FAE?
+FAE=?
+FAE=1
Report active adaptive answer setting: 0 for disabled, 1 for enabled
Report adaptive answer capability
Enable adaptive answer
+FTS=n
Stop transmission and pause, 0-255 in 10 ms
+FRS=n 
Wait for silence, 0-255 in 10 ms 
+FTM=?
Report Class 1 transmit capabilities
+FRM=?
Report Class 1 receive capabilities
+FTH=n
Transmit data with carrier n, 
n = 3, 24, 48, 72, 73, 74, 96, 97, 98, 121, 122, 145, 146
+FRH=n
Receive data with carrier n, 
n = 3, 24, 48, 72, 73, 74, 96, 97, 98, 121, 122, 145, 146 

 

Table 7. PCtel Class 8 (Voice Mode) AT Commands Summary 
Command
Function
ATA
Answering in Voice Mode
ATD
Dial command in Voice Mode
ATH
Hang up in Voice Mode
ATZ
Reset from Voice Mode
AT#BDR
Select baud rate (turn off autobaud)
AT#CID
Enable Caller ID detection and select reporting format
AT#CLS
Select data, fax, or voice
AT#MDL?
Identify model 
AT#MFR?
Identify manufacturer
AT#TL
Transmit level control
AT#REV?
Identify revision level
AT#RG
Record gain control
AT#SPK
Change the setting of Speakerphone
AT#VBS
Bits per sample (ADPCM)
AT#VBT
Beep tone timer
AT#VLS
Voice line select (ADPCM)
AT#VRA
Ringback goes away timer (originate)
AT#VRX
Voice Receive Mode (ADPCM)
AT#VSD
Silence deletion tuner (voice receive, ADPCM)
AT#VSP
Silence detection period (voice receive, ADPCM)
AT#VSS
Silence sensitivity tuner (voice receive)
AT#VTX
Voice Transmit Mode (ADPCM)
AT#VBQ?
Query buffer size
AT#VCI?
Identify compression method (ADPCM)
AT#VRN
Ringback never came timer (originate)
AT#VSK
Buffer skid setting
AT#VSR
Sampling rate selection (ADPCM)
AT#VTD
DTMF/tone reporting capability
AT#VTS
Play tone string (online voice command)

 

Table 8. PCtel Class 8 (Voice Mode) DLE Messages
Code Sent to DTE 
Meaning
<DLE>0 - <DLE>9,
<DLE>*, <DLE>#, 
<DLE>A - <DLE>D
DTMF
Digits 0 through 9, *, #, or A through D detected by the modem. 
<DLE>a
Answer Tone(CCITT)
Send to the DTE when the V.25/T.30 2100 Hz Answer Tone (Data or Fax) is detected. If the DTE fails to react to the code, and the modem continues to detect Answer tone, the code is repeated as often as once every 0.5 second 
<DLE>b
Busy
Send to DTE when the busy cadence is detected. The modem sends the busy <DLE>b code every 4 seconds if busy continues to be detected and the DTE does not react. This allows the DTE the flexibility of ignoring what could be a false busy detection. 
<DLE>c
Calling Tone
Sent when the T.30 1100 Hz Calling Tone (Fax Modem) is detected. The modem assumes the calling tone is valid and sends this code only after 4 seconds of proper cadence has been detected. If the DTE does not react to this code, the code is repeated as often as once every 4 seconds. 
<DLE>d
Dial Tone
Sent in Voice Receive Mode when dial tone is detected after any remaining data in the voice receive buffer. The modem sends this code every 3 seconds if dial tone continues to be detected and the DTE does not react. This allows the DTE the flexibility of ignoring what could be a false dial tone detection. 
<DLE>e
European Data Modem Calling Tone
Sent when the V.25 1300 Hz Calling Tone (Data Modem) is detected. The modem assumes that the calling tone is valid, and sends this code only after 4 seconds of proper cadence has been detected. If the DTE does not react to this code and calling tone continues, the code is sent again as often as once every 4 seconds 
<DLE>f
Bell Answer Tone
Sent when Bell 2225 Hz Answer Tone (Data) is detected. If the DTE fails to react to the code and the modem continues to detect Answer tone, the code is repeated as often as every 0.5 second. 
<DLE>h
Hung Up Handset
Sent immediately when the modem detects that the local handset has hung-up. 
<DLE>q
Quiet
Sent in Voice Receive Mode after any remaining data in the receive voice buffer when the silence detection timer (#VSP) expires and the has been voice data passed to the DTE 
<DLE>s
Silence
Sent in Voice Receive Mode after the silence detection timer (#VSP) expires and if valid voice has not been detected (#VSS).
<DLE>t
Handset Off-Hook
Sent one time when the local handset transition go off-hook.
<DLE><ETX>
End of Stream
This code is sent to denote the end of a voice data stream. 
<DLE><ETX>
Terminate
This code is sent to denote the end of a voice data stream. 
<DLE><CAN>
Cancel
Sent during Voice Transmit Mode to indicate that the DTE has finished transmitting a voice message and wants the modem to discard any remaining data in the voice transmit buffer. The modem immediately purges its buffer, and then responds with VCON message entering Online Voice Command Mode. 
<DLE>p
Pause
Sent during Voice Transmit Mode to force the modem to suspend sending voice data to the selected output device. Any data currently in the voice transmit buffer is saved until either a resume (<DLE>r), or cancel (<DLE><CAN>), is received, in which case the data is lost. If a <DLE><ETX> is received during the paused state, the modem processes it normally, and also automatically resumes transmission of the data left in the buffer (appended with <DLE><ETX>). Any other data received from the DTE while in this paused state is placed in the transmit buffer according to available space, with flow control active.
<DLE>r
Resume
Sent during Voice Transmit Mode to force the modem to resume sending voice data to the selected output device. Any data currently in the voice transmit buffer is now played
AT#VRA
Ringback goes away timer (originate)
AT#VRX
Voice Receive Mode (ADPCM)
AT#VSD
Silence deletion tuner (voice receive, ADPCM)
AT#VSP
Silence detection period (voice receive, ADPCM)
AT#VSS
Silence sensitivity tuner (voice receive)
AT#VTX
Voice Transmit Mode (ADPCM)
AT#VBQ?
Query buffer size
AT#VCI?
Identify compression method (ADPCM)
AT#VRN
Ringback never came timer (originate)
AT#VSK
Buffer skid setting
AT#VSR
Sampling rate selection (ADPCM)
AT#VTD
DTMF/tone reporting capability
AT#VTS
Play tone string (online voice command)

 

Table 9. AT Voice Command Description
Command
Function
ATA
Answering in Voice
This command works similarly to the way it works in Data and Fax Modes. 
Result Code: VCON 
ATD
Dial Command in Voice
This command will perform the dial action in Voice Mode. 
Result Codes: 
VCON
Issued in Voice Mode when the modem determines that the remote modem or handset has gone off-hook.
NO ANSWER
Issues in Voice Mode when the modem determines that the remote has not picked up the line before the S7 timer expires. 
ATH
Hang Up in Voice
This command works the same as in Data and Fax modes by hanging up the phone line. 
  • 1. This command forces the #CLS=0, but does not destroy any of the voice parameter setting such as #VBS, #VSP, etc. 
  • 2. The #BDR setting is forced back to 0. 
ATZ
Reset from Voice Mode
This command works the same as in Data and Fax modes. In addition, it will also reset all voice related parameters to default states, forces the #BDR=0 condition, and forces the telephone line to be selected with the handset on-hook. 
#BDR 
Select Baud Rate (Turn Off Autobaud)
This command select a specific DTE/modem baud rate.
Parameters: n = 0 - 48 (Baud Rate = n * 2400 bps)
Default: 0
Result Codes:
OK if n is between 0 and 48
ERROR Otherwise
Command options:
#BDR? Return the current setting
#BDR=? Return a message indicating the speeds that are supported
#BDR=0 Enable autobaud detection on the DTE interface
#BDR=n Select the baud rate
#CID
Enable Caller ID Detection and Select Reporting Format
This command enables or disables Caller ID recognition and reporting in any mode.
Parameters: n = 0, 1, or 2
Default: 0
Result Codes: OK n = 0, 1, or 2
ERROR Otherwise
Command Options:
#CID? Return the current setting (0, 1, or 2)
#CID=? Return the message, "0-2"
#CID=0 Disables Caller ID
#CID=1 Enable formatted Caller ID reporting of SDM (Single Data Message) and MDM (Multiple Data Message) packets. 
#CID=2 Enable unformatted Caller ID reporting. 
#CLS
Select Data, Fax, or Voice
This command select Data, Fax, or Voice Mode
Parameters: n=0, 1, 2, or 8
Default: 0
Result Codes: OK if n = 0, 1, 2, or 8
ERROR Otherwise
Command options:
#CLS? Return the current setting (0, 1, 2, or 8)
#CLS=? Return the message, "0, 1, 2, 8"
#CLS=0 Select Data Mode.
#CLS=1 Select Class 1 Fax Mode.
#CLS=2 Select Class 2 Fax Mode.
#CLS=8 Select Voice Mode.
#MDL
Identify Model
This command identifies the model number of the modem.
Command option:
#MDL? "PCT288DFV"
#MFR?
Identify Manufacturer
This command identifies the modem manufacturer. 
Command option:
#MFR? "PCtel"
#REV?
Request Revision Level
This command request the revision number of PCtel Driver.
#REV? "PCtel 2.00"
#RG
Record Gain Control
This command sets the record gain.
Parameters: n = 0000 - 7FFF
Default: 7FFF
Result Codes:
OK if n = 0000 - 7FFF
ERROR Otherwise
Command options:
#RG? Return the current setting
#RG=? Return the message, "0000-7FFF" 
RG=n Set the record gain to n
#SPK
Change the setting of Speakerphone
This command set the parameters for speakerphone.
Parameters: #SPK=<mute>, <spk>, <mic>
<mute> Microphone state
0 microphone mute
1 microphone on (default)
2 Room Monitor mode (mic on max. AGC, speaker off)
<spk> Speaker Output Level
Range: 0 to 15 (speaker attenuation in 2 dB steps)
Default: 5 (10 dB attenuation) Speaker mute is achieve by a value of 16
<mic> Microphone Gain Parameter
0 0 dB 
1 6 dB gain (default) 
2 9.5 dB gain 
3 12 dB gain
Command options:
It is not necessary to enter all three parameters,
#SPK=,<spk>,<mic>
#SPK=,,<mic>
#TL
Transmit Level Control
This command sets the transmit level.
Parameters: n = 0000 - 7FFF
Default: 3FFF
Result Codes: OK if n = 0000 - 7FFF
ERROR Otherwise
Command options:
#TL? Return the current setting
#TL=? Return the message, "0000-7FFF"
#TL=n Set the record gain to n
#VBQ?
Query Buffer Size
This command query the modems voice transmit and voice receive buffers size.
Parameters: None
Command option:
#VBQ? Return the size of buffers.
#VBS
Bits Per Sample (Compression Factor)
This command selects the degree of ADPCM voice compression to be used.
Parameters: n = 4 (Only 4 bits per sample compression ratio is supported)
Default: 4
Result Codes: OK if n = 4
ERROR Otherwise
Command options: 
#VBS? Return the current setting 
#VBS=? Return "4" 
#VBS=4 Selects 4 bits per samples. 
#VBT
Beep Tone Timer
This command sets the duration for DTMF tone generation
Parameters: n = 0 - 40 ( duration = n /10 seconds)
Default: 10
Result Codes:
OK if n = 0 - 40 
ERROR Otherwise
Command options:
#VBT? Return the current setting
#VBT=? Returns the message, "0-40"
#VBT=0 Disables the tone generation capability.
#VBT=n Sets tone duration
#VCI?
Identify Compression Method
This command identifies the compression method used by the modem.
Parameter: None
Command option: 
#VCI? Returns the message, "PCtel;ADPCM;32" 
#VLS
Voice Device Selection
This command select which devices is routed through the modem.
Parameter: n = 0, 1, 2, 3, 4, or 6
Default: 0
Result Codes:
OK if n = 0, 1, 2, 3, 4, or 6
ERROR Otherwise
Command options:
#VLS? Return current setting
#VLS=? Return the device types supported by the modem.
#VLS=n Select Device Type (see table below)
Device Type Device Description 
0           Phone Line with Telephone handset 
1           Handset 
2           On-Board Speaker 
3           Microphone 
4           Telephone line with on-board speaker ON and handset 
6           Speaker Phone 
#VRA
Ringback Goes Away Timer (Originate)
When originate a voice call, this command can set the "Ringback Goes Away" timer value, an amount of time measures from when the ringback cadence stops once detected. If ringback is not detected within this period, the modem assumes that the remotes has picked up the line and switches to Online Voice Command Mode. Every time a ringback cadence is detected, this timer is reset.
Parameters: n = 0 - 255 (0 - 2.55 seconds)
Default: 70
Result Codes:
OK if n = 0 - 255
ERROR Otherwise
Command options:
#VRA? Return the current setting
#VRA=? Return the message, "0-255"
#VRA=0 Turn off the timer. The dialing modem sends VCON and enters Online Voice Command Mode after one ringback. 
#VRA=n Set the timer (timer = n * 0.01 seconds) 
#VRN
Ringback Never Came Timer (Originate)
When originating a voice call, this command set the "Ringback Never Came" timer value, an amount of time measured from completion of dialing. If ringback is not detected within this period, the modem assumes the remote has picked up the line and switches to Online Voice Command Mode.
Parameters: n = 0 - 255 (0 - 2.55 seconds)
Result Codes:
OK if n = 0 - 255
ERROR Otherwise
Command option:
#VRN? Return the current setting
#VRN=? Return the message, "0-255"
#VRN=0 Turn off the "Ringback Never Came timer". After dialing, the modem sends VCON and enters Online Voice Command Mode immediately.
#VRN=n Set the timer (duration = n * 0.01 second) 
#VRX
Voice Receive
This command set the modem in Voice Receive Mode.
Parameters: None
Result Codes:
CONNECT When voice transfer from modem to DTE can begin 
ERROR if #VLS=0 and not connected to any input device 
#VSD
Silence Deletion Tuner (Voice Receive)
This command can enable/disable Voice Receive Mode silence detection. Silence Deletion is not supported in PCtel HSP Modem.
Parameters: n = 0
Default: 0
Result Codes:
OK if n = 0
ERROR Otherwise
Command options: 
#VSD? Return current setting 
#VSD=? Return the message, "0" 
#VSD=0 Disable Silence Deletion 
#VSK
Buffer Skid Setting
This command queries and sets the number of bytes of spare space, after the XOFF threshold is reached, in the modems buffer during Voice Transmit Mode. This equates to the "skid" spare buffer space, or the amount of data the DTE can continue to send after being told to stop sending data by the modem, before the modem voice transmit buffer overflows.
Parameters: n = 0 - 255
Default: 255
Result Code:
OK if n = 0 - 255
ERROR Otherwise
Command options:
#VSK? Return the current setting
#VSK=? Return the message, "0-255"
#VSK=n Set the skid buffer size to n bytes 
#VSP
Silence Detection Period (Voice Receive)
This command sets the Voice Receive Mode silence detection period value. If the modem does not receive any ADPCM data after the timer expired, it will cause the modem to send <DLE>s or <DLE>q codes.
Parameters: n = 0 - 255 (0 - 25.5 seconds)
Default: 55
Result Code:
OK if n = 0 - 255
ERROR Otherwise
Command options:
#VSP? Return current setting
#VSP=? Return the message, "0-255"
#VSP=0 Disable the silence period detection timer
#VSP=n timer = n * 0.1 second
#VSR
Sampling Rate Selection
This command sets the audio codec sampling rate.
Parameters: n = 8000 (8000 Hz sampling rate)
Default: 8000
Result Codes: OK if n = 8000
ERROR Otherwise
Command options:
#VSR? Return the current setting
#VSR=? Return the message, "8000"
#VSR=8000 Set the sample rate to 8000
#VSS
Silence Sensitivity Tuner (Voice Receive)
This command set the sensitivity in Voice Receive Mode silence detection.
Parameters: n = 0 - 3
Default: 2
Result Codes:
OK if n = 0 -3
ERROR Otherwise
Command options:
#VSS? Return current setting
#VSS=? Return the message, "0-3"
#VSS=0 Disable silence detection by the modem in Voice Receive Mode
#VSS=1 Least sensitive setting #VSS=2 Medium sensitive setting
#VSS=3 Most sensitive setting
#VTD
Tone Reporting Capability
This command sets which types of tones can be detected and reported to the DTE via shielded codes in Voice Transmit, Voice Receive, and Online Voice Command Modes.
Parameters: i, j, k
Default: 3F, 3F, 3F
Result Codes:
OK if setting are supported by the modem.
ERROR Otherwise
Command options:
#VTD? Return current setting
#VTD=? Returns the tone reporting capabilities of the modem. 
#VTD=i,j,k Where i, j, k corresponds to the desired capabilities (see table below), i for Voice Transmit, j for Voice Receive, and k for Online Voice Command Modes.
Bit Description
0   0/1=Disable/Enable DTMF tone capability
1   0/1=Disable/Enable V.25 1300 Hz Calling tone capability
2   0/1=Disable/Enable V.30 1100 Hz Facsimile Calling tone
    capability
3   0/1=Disable/Enable V.25/T.30 2100 Hz Answer tone capability
4   0/1=Disable/Enable Bell 2225 Hz Answer tone capability
5   0/1=Disable/Enable call progress tone and cadence 
    tone capability 
#VTS
Play Tone String (Online Voice Command Mode)
This command can play one or more DTMF or other tones. No key abort is allowed.
Dual or Single Tones:
These are represented by a substring enclosed in square brackets ("[ ]") within the parameter. Each such substring consists of three sub-elements corresponding to 2 frequencies in Hertz (0, or 2000-3000) and a duration (ASCII decimal in units of 100ms).
Varying DTMF Digits:
This is represented by a substring enclosed in curly braces ("{ }") within the parameter. Each such substring consists of two sub-elements corresponding to a DTMF digits (0-9, A-D, *, #), and alternate duration in units of 100ms.
Parameters:
The tone generation consists of elements in a list with each element separated by commas.
Result Codes:
OK Command to play tones on currently selected device is accepted. 
ERROR Command was not issued in Online Voice Command Mode or string is grammatically incorrect. 
#VTX
Voice Transmit
This command set the modem in Voice Transmit Mode. The #VLS command should have been previously issued correctly.
Parameters:
None
Result Codes: 
CONNECT When voice transmission by DTE can begin.
ERROR If #VLS=0 and output device is not connected.

%P - PTT Testing Utilities

This facility testing of signal levels provides a continuous signal when the modem is in IDLE mode. This allows the user to initiate a series of signal that are necessary for PTT approval. These signals are answer tone, carriers, modulation, and other pertinent signals. A selected test will be terminated when any keyboard character is entered. The followings are command's description.

Note: For DTMF, the transmit level is -10dBm for low band and -8dBm for high band, inter digit delay is fixed at 70ms. All other transmit level is adjustable according to the setting of register S91 (from -10 to -15dBm). Speaker control initiates by command ATLn.
 

Command
Function
%P00 - %P09
DTMF tone digits from 0 to 9. 
%P10
DTMF digit A.
%P11
DTMF digit B.
%P12
DTMF digit C.
%P13
DTMF digit D.
%P14
DTMF digit *.
%P15
DTMF digit #.
%P16
V.21 Channel 1 mark 980 Hz.
%P17
V.21 Channel 2 mark 1650 Hz.
%P18
V.23 Reversed channel mark 390 Hz.
%P19
V.23 Forward channel mark 1300 Hz.
%P20
V.22 Originate.
%P21
V.22bis originate.
%P22
V.22 Answer.
%P23
V.22bis Answer.
%P24
V.21 Channel 1 space 1180 Hz.
%P25
V.21 Channel 2 space 1850 Hz.
%P26
V.23 Reversed channel space 450 Hz.
%P27
V.23 Forward channel space 2100 Hz.
%P28
V.32 at 9600 bps.
%P29
V.32bis 14400 bps.
%P30
Silence, off-hook.
%P31
V.25 Answer tone 2100 Hz.
%P32
Guard tone 1800 Hz. 
%P33
V.25 Calling tone 1300 Hz.
%P34
Fax calling tone 1100 Hz. 
%P35
V.21 Channel 2 1650 Hz.
%P36
V.27ter 2400 bps.
%P37
V.27ter 4800 bps.
%P38
V.29 7200 bps.
%P39
V.29 9600 bps.
%P40
V.17 7200 bps long train.
%P41
V.17 7200 bps short train.
%P42
V.17 9600 bps long train.
%P43
V.17 9600 bps short train.
%P44
V.17 12000 bps long train.
%P45
V.17 12000 bps short train.
%P46
V.17 14400 bps long train.
%P47
V.17 14400 bps short train.
%P48
V.34, 2400 bps modulation.
%P49
V.34, 4800 bps modulation.
%P50
V.34, 7200 bps modulation.
%P51
V.34, 9600 bps modulation.
%P52
V.34, 12000 bps modulation.
%P53
V.34, 14400 bps modulation.
%P54
V.34, 16800 bps modulation.
%P55
V.34, 19200 bps modulation.
%P56
V.34, 21600 bps modulation.
%P57
V.34, 24000 bps modulation.
%P58
V.34, 26400 bps modulation.
%P59
V.34, 28800 bps modulation.
%P60
V.32bis 9600 bps modulation.
%P61
V.32bis 12000b ps modulation.
%P62
Bell 212A originate 1200 bps
%P63
Bell 212A answer 1200 bps
%P64
Bell 103 originate mark 1270 Hz
%P65
Bell 103 originate space 1070 Hz
%P66
Bell 103 answer mark 2225 Hz
%P67
 Bell 103 answer space 2025 Hz
%P99,n
where 0<= n <=23 
f(Hz) = n * (150Hz) 
n   f(Hz) 
0   0      modem goes off hook and reports power level of
           incoming signal if present
1   150
2   300
3   450
4   600
5   750
6   900
7  1050
8  1200
9  1350
10 1500
11 1650
12 1800
13 1950
14 2100
15 2250
16 2400
17 2550
18 2700
19 2850
20 3000
21 3150
22 3300
23 3450

%I or %I? Country Code Selection and Identification

This command provides the ability of selection the desired country telephony Central Office. When the selection is correct, a set of the selected country parameters will be loaded for the current operation.
 

Country n
USA
1
France
2
Germany
3
Italy
4
Sweden
5
UK
6
Japan
7
Australia
8
Spain
9
Taiwan
10
Singapore
11
Korea
12
Switzerland
13
Norway
14
Netherlands
15
Belgium
16
Canada
17
Ireland
18
Portugal
19
Poland
20
Hungary
21
Finland
22
Denmark
23
Result Codes:
OK If correct selection. 
ERROR Otherwise.
Command format:
AT%I?
Result Codes:
country name CO ( Central Office) 
ERROR Otherwise.