U.S. ROBOTICS, INC.
AUTO DIAL 21A
| 
 Card Type  | 
 Modem (asynchronous)  | 
| 
 Chip Set  | 
 U.S. Robotics  | 
| 
 Maximum Data Rate  | 
 1200bps  | 
| 
 Data Bus  | 
 External  | 
| 
 Data Modulation Protocol  | 
 Bell 212A  | 
V2252
| 
 CONNECTIONS  | ||||||
| 
 Function  | 
 Label  | 
 Function  | 
 Label  | |||
| 
 Line out/in - unidentified  | 
 CN1  | 
 DC power  | 
 CN4  | |||
| 
 Line in/out - unidentified  | 
 CN2  | 
 Power switch  | 
 SW1  | |||
| 
 RS-232/422  | 
 CN3  | 
 Analog loopback switch  | 
 SW2  | |||
| 
 USER CONFIGURABLE SETTINGS  | ||
| 
 Setting  | 
 Label  | 
 Position  | 
| 
 Auto answer disabled  | 
 SW3/A  | 
 Off  | 
| 
 Auto answer enabled  | 
 SW3/A  | 
 On  | 
| 
 CD normal  | 
 SW3/B  | 
 On  | 
| 
 CD forced high  | 
 SW3/B  | 
 Off  | 
| 
 Equalize for dial-up phone lines  | 
 SW3/C  | 
 Off  | 
| 
 Equalize for dedicated phone lines  | 
 SW3/C  | 
 On  | 
| 
 DTR normal  | 
 SW3/D  | 
 Off  | 
| 
 DTR forced high  | 
 SW3/D  | 
 On  | 
| 
 RS232C  | ||||
| 
 Setting  | 
 SW4/A  | 
 SW4/B  | 
 SW4/C  | 
 SW4/D  | 
| 
 Pin 2 receive/Pin 3 send  | 
 On  | 
 On  | 
 Off  | 
 Off  | 
| 
 Pin 2 send/Pin 3 receive  | 
 Off  | 
 Off  | 
 On  | 
 On  | 
| 
 MISCELLANEOUS TECHNICAL NOTES  | 
| 
 Note: Diagram not available.  | 
| 
 DIAGNOSTIC LED(S)  | |||
| 
 LED  | 
 Color  | 
 Status  | 
 Condition  | 
| 
 CD  | 
 Red  | 
 On  | 
 Carrier signal detected  | 
| 
 CD  | 
 Red  | 
 Off  | 
 Carrier signal not detected  | 
| 
 HS  | 
 Red  | 
 On  | 
 Modem is operating at 1200bps  | 
| 
 HS  | 
 Red  | 
 Off  | 
 Modem is operating at slower than 1200bps  | 
| 
 OH  | 
 Red  | 
 On  | 
 Modem is off-hook  | 
| 
 OH  | 
 Red  | 
 Off  | 
 Modem is on-hook  | 
| 
 TR  | 
 Red  | 
 On  | 
 DTR signal is high  | 
| 
 TR  | 
 Red  | 
 Off  | 
 DTR signal is low  | 
| 
 RD  | 
 Red  | 
 On  | 
 Modem is receiving data  | 
| 
 RD  | 
 Red  | 
 Off  | 
 Modem is not receiving data  | 
| 
 AN  | 
 Red  | 
 On  | 
 Auto-answer enabled  | 
| 
 AN  | 
 Red  | 
 Off  | 
 Auto-answer disabled  | 
| 
 SD  | 
 Red  | 
 On  | 
 Modem is transmitting data  | 
| 
 SD  | 
 Red  | 
 Off  | 
 Modem is not transmitting data  | 
| 
 AL  | 
 Red  | 
 On  | 
 Modem is in analog loopback test mode  | 
| 
 AL  | 
 Red  | 
 Off  | 
 Modem is not in analog loopback test mode  | 
| 
 ON  | 
 Red  | 
 On  | 
 Power is on  | 
| 
 ON  | 
 Red  | 
 Off  | 
 Power is off  | 
Proprietary AT Command Set
| 
 ABORT  | |
| 
 Type:  | 
 Immediate  | 
| 
 Format:  | 
 Any key  | 
| 
 Description:  | 
 Aborts dialing command issued; modem hangs up.  | 
| 
 ANSWER  | |
| 
 Type:  | 
 Immediate  | 
| 
 Format:  | 
 AT [cmds] A  | 
| 
 Description:  | 
 Enables answer mode, the modem goes off-hook.  | 
| 
 ATTENTION  | |
| 
 Type:  | 
 Immediate  | 
| 
 Format:  | 
 AT [cmds]  | 
| 
 Description:  | 
 Tells the modem that a command follows or use alone to test OK result code  | 
| 
 DIAL  | |
| 
 Type:  | 
 Immediate  | 
| 
 Format:  | 
 AT [cmds] D<#> [cmds]  | 
| 
 Example:  | 
 ATDT 443-3388,,,1111;  | 
| 
 Description:  | 
 Dials telephone number according to any modifiers included in the string  | 
| 
 Note:  | 
 Any combination of modifiers can be used to produce the desired dial functions in sequence.  | 
| 
 Command  | 
 Function  | 
| 
 í P | 
 Pulse dialing enabled  | 
| 
 T  | 
 Tone dialing enabled  | 
| 
 ,  | 
 Dialing paused for 2 seconds  | 
| 
 ECHO  | |
| 
 Type:  | 
 Configuration  | 
| 
 Format:  | 
 AT [cmds] En [cmds]  | 
| 
 Description:  | 
 Controls echo function; display keyboard commands when enabled.  | 
| 
 Command  | 
 Function  | 
| 
 í E0 | 
 Echo function disabled  | 
| 
 E1  | 
 Echo function enabled  | 
| 
 ECHO - ON-LINE  | |
| 
 Type:  | 
 Configuration  | 
| 
 Format:  | 
 AT [cmds] Fn [cmds]  | 
| 
 Description:  | 
 Selects whether commands sent while in data mode are echoed  | 
| 
 Command  | 
 Function  | 
| 
 F0  | 
 Local echo enabled  | 
| 
 í F1 | 
 Local echo disabled  | 
| 
 ESCAPE SEQUENCE  | |
| 
 Type:  | 
 Immediate  | 
| 
 Format:  | 
 +++AT [cmds] <CR> | 
| 
 Description:  | 
 Initiates the escape sequence and returns the modem to the on-line command state if it receives three escape characters set in S2 within the time allotted by S12.  | 
Note: Do not precede this command with AT. | |
| 
 PULSE DIALING  | |
| 
 Type:  | 
 Configuration  | 
| 
 Format:  | 
 AT [cmds] P [cmds]  | 
| 
 Description:  | 
 Enables pulse dialing  | 
Note: This command can be duplicated with the P modifier in the D (Dial) command. | |
| 
 REPEAT PREVIOUS COMMAND  | |
| 
 Type:  | 
 Immediate  | 
| 
 Format:  | 
 A/  | 
| 
 Description:  | 
 Repeats previous command, mainly used for redial  | 
Note: Do not precede this command with AT, or follow it with <CR>. | |
| 
 RESET  | |
| 
 Type:  | 
 Immediate  | 
| 
 Format:  | 
 AT [cmds] Z [cmds]  | 
| 
 Description:  | 
 Resets the modem and clears all registers to default values  | 
| 
 RESULT CODES  | |
| 
 Type:  | 
 Configuration  | 
| 
 Format:  | 
 AT [cmds] Qn [cmds]  | 
| 
 Description:  | 
 Enables modem to send result codes to the DTE  | 
| 
 Command  | 
 Function  | 
| 
 í Q0 | 
 Result code sending enabled  | 
| 
 Q1  | 
 Result code sending disabled  | 
| 
 RESULT CODE FORMAT  | |
| 
 Type:  | 
 Configuration  | 
| 
 Format:  | 
 AT [cmds] Vn [cmds]  | 
| 
 Description:  | 
 Selects word or numeric format for information-text and result codes  | 
| 
 Command  | 
 Function  | 
| 
 V0  | 
 Numeric format enabled  | 
| 
 í V1 | 
 Verbose (word) format enabled  | 
| 
 SELECT CALL PROGRESS RESULT CODES  | |
| 
 Type:  | 
 Configuration  | 
| 
 Format:  | 
 AT [cmds] Xn [cmds]  | 
| 
 Description:  | 
 Enables selection of tone detection and associated result code format options  | 
| 
 Command  | 
 Function  | 
| 
 í X0 | 
 Extended result codes disabled; result codes 0-4 enabled.  | 
| 
 X1  | 
 Extended result codes enabled; result codes 0-5 enabled  | 
| 
 SPEAKER MODE  | |
| 
 Type:  | 
 Configuration  | 
| 
 Format:  | 
 AT [cmds] Mn [cmds]  | 
| 
 Description:  | 
 Selects various speaker options  | 
| 
 Command  | 
 Function  | 
| 
 M0  | 
 Speaker disabled  | 
| 
 í M1 | 
 Speaker enabled until carrier signal detected  | 
| 
 M2  | 
 Speaker enabled  | 
| 
 STATUS-REGISTER  | ||
| 
 Type:  | 
 Configuration  | |
| 
 Format:  | 
 AT [cmds] Sn=x [cmds]  | |
| 
 Description:  | 
 Writes to a specified register, values ranging from 0-255.  | |
| 
 Command  | 
 Function  | |
| 
 S0=x  | 
 Sets the number of rings allowed before the modem automatically goes off-hook. S0=0 will disable auto-answer.  | |
| 
 S2=x  | 
 Selects a character used for the escape sequence. Default = 43  | |
| 
 S7=x  | 
 Maximum wait time in seconds the modem uses after dialing to detect a carrier signal from the remote modem for both originating and answering calls. Default = 30  | |
| 
 TONE DIALING  | |
| 
 Type:  | 
 Configuration  | 
| 
 Format:  | 
 AT [cmds] T [cmds]  | 
| 
 Description:  | 
 Enables tone dialing mode  | 
Note: This command can be duplicated with the T modifier in the D (Dial) command.  | |