USR5686G 56K V.92 Serial Controller Faxmodem(005686-06, 64-005686-06R) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Electronic product documentation is provided as a courtesy to USRobotics customers. These are electronic versions of the original documentation. Some of the information contained within this documentation, including the support contact information, is subject to change. |
&
for Hayes and USR, and
for Microcom, for instance. Many of these re-standardized on the Hayes extensions after the introduction of the SupraFAXModem 14400 and the subsequent market consolidation that followed.AT&F&D2&C1S0=0X4
. This is called the initialization string.[5] The V.250 specification requires all DCEs to accept a body (after 'AT') of at least 40 characters of concatenated commands.[6]Modem A | Modem B | Comment |
---|---|---|
ATDT15551234 | User at modem A issues a dial command: AT-Get the modem's ATtention; D-Dial; T-Touch-Tone; 15551234-Call this number | |
RING | Modem A begins dialing. Modem B's phone-line rings, and the modem reports the fact. | |
ATA | Computer at modem B issues answer command. | |
CONNECT | CONNECT | The modems connect, and both modems report 'connect'. (In practice, most modems report more information after the word CONNECT — specifying the speed of the connection.) Also, at this time, both modems will raise the DCD, or Data Carrier Detect signal, on the serial port. |
abcdef | abcdef | When the modems are connected, any characters typed at either side will appear on the other side. The person at computer A starts typing. The characters pass through the modem and appear on computer B's screen. (User A may not see his own typed characters — depending on the terminal software's local echo setting). |
+++ | The person at computer B issues the modem escape command. (Alternately, and more commonly, the computer B could drop the DTR, or Data Terminal Ready signal, to achieve a hangup, without needing to use +++ or ATH.) | |
OK | The modem acknowledges it. | |
ATH | The person at computer B issues a hang up command. | |
NO CARRIER | OK | Both modems report that the connection has ended. Modem B responds 'OK' as the expected result of the command; modem A says NO CARRIER to report that the remote side interrupted the connection. The modems on both sides drop their DCD signals as well. |
Command | Description | Comments |
---|---|---|
A0 or A | Answer incoming call | |
A/ | Repeat last command | Do not preface with AT, do not follow with carriage return. Enter usually aborts. |
D | Dial | Dial the following number and then handshake P - Pulse Dial T - Touch Tone Dial W - Wait for the second dial tone R - Reverse to answer-mode after dialing @ - Wait for up to 30 seconds for one or more ringbacks , - Pause for the time specified in register S8 (usually 2 seconds) ; - Remain in command mode after dialing. ! - Flash switch-hook (Hang up for a half second, as in transferring a call.) L - Dial last number |
E0 or E | No Echo | Will not echo commands to the computer |
E1 | Echo | Will echo commands to the computer (so one can see what one types) |
H0 or H | Hook Status | On hook. Hangs up the phone, ending any call in progress. |
H1 | Hook status | Off hook. Picks up the phone line (typically you'll hear a dialtone) |
I0 to I9 | Inquiry, Information, or Interrogation | This command returns information about the model, such as its firmware or brand name. Each number (0 to 9, and sometimes 10 and above) returns one line of modem-specific information, or the word ERROR if the line is not defined. Today, Windows uses this for Plug-and-play detection of specific modem types. |
L0 or Ln (n=1 to 3) | Speaker Loudness. Supported only by some modems, usually external ones. Modems lacking speakers, or with physical volume controls, or ones whose sound output is piped through the sound card will not support this command. | Off or low volume |
M0 or M | Speaker off, completely silent during dialing | M3 is also common, but different on many brands |
M1 | Speaker on until remote carrier detected (i.e. until the other modem is heard) | |
M2 | Speaker always on (data sounds are heard after CONNECT) | |
O | Return Online | Returns the modem back to the normal connected state after being interrupted by the '+++' escape code. |
Q0 or Q | Quiet Mode | Off - Displays result codes, user sees command responses (e.g. OK) |
Q1 | Quiet Mode | On - Result codes are suppressed, user does not see responses. |
Sn | Select current register Note that Sn, ? and =r are actually three separate commands, and can be given in separate AT commands. | Select register n as the current register |
Sn? | Select register n as the current register, and query its value. Using ? on its own will query whichever register was most recently selected. | |
Sn=r | Select register n as the current register, and store r in it. Using =r on its own will store into whichever register was most recently selected. | |
V0 or V | Verbose | Numeric result codes |
V1 | English result codes (e.g. CONNECT, BUSY, NO CARRIER etc.) | |
X0 or X | Smartmodem | Hayes Smartmodem 300 compatible result codes |
X1 | Usually adds connection speed to basic result codes (e.g. CONNECT 1200) | |
X2 | Usually adds dial tone detection (preventing blind dial, and sometimes preventing ATO) | |
X3 | Usually adds busy signal detection. | |
X4 | Usually adds both busy signal and dial tone detection | |
Z0 or Z | Reset | Reset modem to stored configuration. Use Z0, Z1 etc. for multiple profiles. This is the same as &F for factory default on modems without NVRAM (non volatile memory) |
Register | Description | Range | Default value |
---|---|---|---|
S0 | Number of rings before Auto-Answer | 0–255 (0 = never) | 0 |
S1 | Ring Counter | 0–255 rings | 0 |
S2 | Escape character | 0–255, ASCII decimal | 43 ('+') |
S3 | Carriage Return Character | 0–127, ASCII decimal | 13 (Carriage Return) |
S4 | Line Feed Character | 0–127, ASCII decimal | 10 (Line Feed) |
S5 | Backspace Character | 0–32, ASCII decimal | 8 (Backspace) |
S6 | Wait Time before Blind Dialing | 2–255 seconds | 2 |
S7 | Wait for Carrier after Dial | 1–255 seconds | 50 |
S8 | Pause Time for Comma (Dial Delay) | 0–255 seconds | 2 |
S9 | Carrier Detect Response Time | 1–255 tenths of a seconds | 6 (0.6 second) |
S10 | Delay between Loss of Carrier and Hang-Up | 1–255 tenths of a second | 14 (1.4 seconds) |
S11 | DTMF Tone Duration | 50–255 milliseconds | 95 milliseconds |
S12 | Escape Code Guard Time | 0–255 fiftieths of a second | 50 (1 second) |
S18 | Test Timer | 0–255 seconds | 0 seconds |
S25 | Delay to DTR | 0–255 (seconds if synchronous mode, hundredths of a second in all other modes) | 5 |
S26 | RTS to CTS Delay Interval | 0–255 hundredths of a second | 1 hundredth of a second |
S30 | Inactivity Disconnect Timer | 0–255 tens of seconds | 0 (disable) |
S37 | Desired Telco Line Speed | 0–10 Command options:
| 0 |
S38 | Delay before Force Disconnect | 0–255 seconds | 20 seconds |
Leading characters | Includes commands related to |
---|---|
+A | Call control (network Addressing) issues, common, PSTN, ISDN, ITU-T Rec. X.25, switched digital |
+C | Digital Cellular extensions |
+D | Data Compression, ITU-T Rec. V.42 bis |
+E | Error Control, ITU-T Rec. V.42 |
+F | Facsimile, ITU-T Rec. T.30, etc. |
+G | Generic issues such as identity and capabilities |
+I | DTE-DCE Interface issues, ITU-T Rec. V.24, etc. |
+M | Modulation, ITU-T Rec. V.32 bis, etc. |
+P | PCM DCE commands, ITU-T Rec. V.92 |
+S | Switched or Simultaneous Data Types |
+T | Test issues |
+V | Voice extensions |
+W | Wireless extensions |
Command | Description |
---|---|
AT+CPIN=1234 | Enter PIN code |
AT+CPWD='SC','old','new' | Change PIN code from 'old' to 'new' |
AT+CLCK='SC',0,'1234' | Remove PIN code |
AT&V | Status |
ATI | Status (Manufacturer, Model, Revision, IMEI, capabilities) |
AT+COPS=? | List available networks 0-Unknown/2-Current/3-Forbidden, Longname, Shortname, Numerical-ID, 'AcT' |
AT+CSQ | Get signal strength. Answer: +CSQ: <rssi (more=better)>, <ber, less=better> |
ATD*99# | Dial access point |
AT+CGDCONT=1,'IP','access.point.name' | Defines PDP context[9] |
The Wikibook Serial Programming has a page on the topic of: Serial Programming: Modems and AT Commands |