3COM CORPORATION MICRO LINK 1200 Card Type Modem (asynchronous) Chip Set U.S. Robotics Maximum Data Rate 1200bps/300bps Data Bus External Data Modulation Protocol Bell 212A 54162 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 SW3/A Off Continuous answer SW3/A On CD normal SW3/B Off CD forced high SW3/B On 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 A/A1 normal J/1 Unidentified A/A1 low when modem is off-hook J/1 Unidentified 10-bit character transmission J/2 Unidentified 11-bit character transmission J/2 Unidentified Future application - factory configured, do J/3 Unidentified not alter Reset J/14 Unidentified RS232C Setting SW4/A SW4/B SW4/C SW4/D Pin 2 receive/Pin 3 On On Off Off send Pin 2 send/Pin 3 Off Off On On receive SERIAL PORT ADDRESS Setting Setting J/10 J/11 J/12 COM1 (3F8h) IRQ4 On On On COM2 (2F8h) IRQ3 On Off Off COM3 (3E8h) IRQ4 Off On On COM4 (2E8h) IRQ3 Off Off Off DIAGNOSTIC LED(S) LED Color Status Condition CD Red On Carrier signal detected CD Red Off Carrier signal not detected ON Red On Power is on ON Red Off Power is off AL Red On Modem is in analog loopback test mode AL Red Off Modem is not in analog loopback test mode SD Red On Modem is transmitting data SD Red Off Modem is not transmitting data RD Red On Modem is receiving data RD Red Off Modem is not receiving data MISCELLANEOUS TECHNICAL NOTES Note: Diagram not available. 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 P Pulse dialing enabled T Tone dialing enabled , Dialing paused for 2 seconds to a maximum amount of time specified in S8 register ECHO Type: Configuration Format: AT [cmds] En [cmds] Description: Controls echo function; display keyboard commands when enabled. Command Function 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 F1 Local echo disabled ESCAPE SEQUENCE Type: Immediate Format: +++AT [cmds] 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. 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 . RESULT CODES Type: Configuration Format: AT [cmds] Qn [cmds] Description: Enables modem to send result codes to the DTE Command Function 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 V1 Verbose (word) format enabled SPEAKER MODE Type: Configuration Format: AT [cmds] Mn [cmds] Description: Selects various speaker options Command Function M0 Speaker disabled 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. Default = 1 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 = 17