2400/9600 BPS Faxmodem (250-3027B) Command Mode Faxback Doc. # 5754 To send commands to your modem, you must be running a communications program. SWITCHING FROM THE COMMUNICATIONS TO THE COMMAND MODE Escape Code The escape code is a code you send to your modem to make it switch from the communications mode to the command mode. When you switch modes, the modem does not disconnect from the phone line. It merely suspends the transfer of information. The default escape code sequence is: Wait at least 1 second without typing a character. Type +++ Wait at least 1 second for the modem to acknowledge. Your modem acknowledges by sending OK (or 0 if you turn off word result codes). The reason for the 1 second wait before and after sending the escape code is to prevent accidentally switching modes. If you type anything within 1 second (the escape code guard time) of the escape code, your modem ignores the escape code. Your can change the default values of the escape code and the escape code guard time. The escape code is a single character you enter three times. Surrounded by a designated period of time. Refer to "Internal Modem Registers," Registers S2 and S12, to change the default values. COMMAND SYNTAX This section describes the various elements that make up all modem commands. ATTENTION All commands must begin with the letters AT. AT is short for "Attention" and you modem uses these letters to automatically set the speed and the parity. You can enter AT and all other commands in either upper or lower case. LINE LENGTH LIMITS You can type one or more commands after the AT. You modem performs the commands in the order given. The number of commands you can give at one time is limited by the line length, which cannot exceed 42 characters. Your modem does not count control characters and spaces, but it does count punctuation marks such as dashes or commas. CARRIAGE RETURN ENTER denotes a carriage return. This ends the command; your modem does not process the command until it seed the ENTER. LINE EDITING After you enter a command (before you press ENTER), you can edit the command using the backspace key, which deletes the last character you entered. NOTE: If you backspace over a space, your modem ignores the space and erases the next character. In this case, your computer does not display the command properly. PARAMETERS Most commands consist of a single letter followed by a single-digit parameter, or option. If you do not follow the command with a parameter, your modem assumes a parameter of 0. REPEAT (A/) Repeats the command line. Neither AT nor ENTER is necessary with this command. EXAMPLE COMMAND The following are two examples of valid modem commands. AT X4 V1 DT (408) 555-3438 ENTER ATXVDT4085553438 ENTER Note that you do not need to enter any spaces. But spaces make the command easier to read (although, usually harder to edit). COMMAND RESULTS After you enter the command (ENTER), your modem executes the command line and returns a result code. Your modem can express this result code as a word or a number. Also, you can select which result codes your modem uses, and even turn result codes on and off. The V, X, and Q commands control these options, and are discussed later in this chapter. Below are the ten result codes and their meanings. NUMBER WORD DESCRIPTION 0 OK The modem successfully processed the command line. 1 CONNECT The modem detected a carrier at 300 BPS. 2 RING The phone is ringing. 3 NO CARRIER Carrier not detected within time limit, or carrier lost. 4 ERROR The modem could not process the command line (entry error). 5 CONNECT 1200 The modem detected a carrier at 1200 BPS. 6 NO DIALTONE The modem could not detect a dialtone when dialing. 7 BUSY Modem detected a busy signal. 8 NO ANSWER Modem never detected silence (@ command only). 9 NOT USED 10 CONNECT 2400 The modem detected a carrier at 2400 BPS. TRANSMISSION SPEED When you type AT to get our modem's attention, your modem sets itself to the speed you have set using your communications program. When you connect to another computer either by dialing or auto-answer, your modem connects at the other computer's highest speed (but not greater than the AT speed) and sends you a CONNECT result code. Then your modem changes its operation to the other computer's speed (if different from the AT speed). If the connect speed differs from the speed you set in your communications program, you do not need to change your communications program's speed. The characters display on your screen at the slower rate, automatically. For example, if you set your communications software to operate at 2400 BPS, type AT DT 555-3434 ENTER, and the system you dial answers at 1200 BPS, you see the message CONNECT 1200. Communications then proceed as normal, but at the slower speed. The connect result codes are: CONNECT (110 or 300 BPS connection) CONNECT 1200 (1200 BPS connection) CONNECT 2400 (2400 BPS connection) DIALING COMMAND AND OPTIONS This sections describes the dialing command and its options. Dial Command (D) D is the dial command. You can enter several other associated commands as part of a dial command. In its simplest form, follow the dial command with the number you want the modem to dial. AT D 555-8900 ENTER NOTE: Your modem ignores the spaces and the dash (-). Your modem dials the number and waits 30 seconds (default) for a response from the called modem. If the other modem answers, your modem sends the CONNECT, CONNECT 1200, or CONNECT 2400 result code, depending on the other modem's speed. Your modem then enters the communication mode and begins communicating with the other system. If your modem does not hear another modem, it returns a NO CARRIER or BUSY result code. PAUSE (,) A comma in the dial sequence tells your modem to pause two seconds, then continue. You might want to use this if you dial from a system where you have to access an outside line, then dial the outside number. ATD9, 555-8912 ENTER Dial 9, pause for 2 seconds, then dial 555-8912. NOTE: You can use more than one comma to increase the pause time, or change the time by setting Register S8. WAIT FOR DIAL TONE (W) A (W) in the dial sequence tells your modem to wait for a dial tone. You could use this if you use an alternate long-distance carrier, or if you dial from a system that requires an access code for a long distance number: ATD23W555-1893 ENTER Dial 23, wait for a dial tone, dial 555-1893. The X command and the contents of Register S7 determine how long the modem waits for the dial tone, If you set X2 or X4, your modem waits for 5 seconds. Other wise, your modem waits for the timeset by Register S7. If your modem does not hear a dial tone within the specified time, it returns NO DIALTONE. WAIT FOR SILENCE (@) An @ in the dial sequence causes your modem to wait for 5 seconds of silence after one or more rings. You could use this if you dial a long-distance service that does not produce a second dial tone. Your modem waits the length of time specified in Register S7 (default 30 seconds) for the 5 seconds of silence. If the modem does not detect silence, it returns to NO ANSWER or BUSY result code. ATDT 555-2323@23ENTER Dial 555-2323, wait for silence, dial 23. SWITCH HOOK FLASH (!) An ! causes the modem to perform a flash. This makes the modem hangup the phone line for about 0.5 seconds (like pressing and releasing the switch hook on your telephone). Some phone systems use this function to transfer calls. ATDT555-3439! ENTER Dial 555-3439, flash. TOUCH TONE DIALING (T) PULSE DIALING (P) The T and P dial modifiers select the dialing method your modem uses. Your modem defaults to using pulse dialing. You could use this to use alternate long-distance services from a pulse-dial line. ATD9WT 555-2322 ENTER Dial 9 pulse mode, wait for a dial tone, dial 555-2322 in tone mode. Your modem dials using the last method used, so, in the above example, any additional dial commands use touch tone unless you specify pulse. MEMORY DIAL NUMBER (S=n) S=n (where n is 0-3) in the dial sequence makes the modem dial one of four telephone numbers you previously stored using the &Zn command. ATDS=1ENTER Dial the number stored in redial memory 1. RETURN TO COMMAND MODE (;) A ; in the dial sequence tells your modem to return to the command mode as soon as it finishes dialing. The modem does not try to detect a carrier. You would use this command when you use the modem to dial a voice call. ATD 555-8373; ENTER Dial 555-8373. AUTO-DIALING VOICE CALLS You can have your modem dial any telephone number, even if a computer is not connected to the other phone. Lift your telephone handset, send the dialing command, and listen for the other party to answer. At any time after the dialing stops, you can press any key to disconnect your modem. ATDT 555-1281; ENTER Dial 555-1281. When the person answers, press any key to disconnect the modem. DIALING TIMING PARAMETERS Registers S6 through S11 control the timing of the dialing commands. Refer to "Internal Modem Registers" for complete information about these registers. AUTO ANSWER OPERATION You can set your modem to automatically answer calls. This can be a useful feature if you need to access your computer from another computer. As set at the factory, the modem does not automatically answer incoming calls. You control the auto answer feature using Register S0 which determines the number of rings before your modem answers. If you set the register to 0 (default) the modem does not automatically answer the phone. Otherwise, the modem waits for the number of rings you specify (1-255). AT S0=1 ENTER The modem answers after one ring. AT S0=5 ENTER The modem answers after five rings. AT S0=23 ENTER The modem answers after 23 rings. After the modem answers, it sends an answer tone and waits for an originate tone. If the modem hears an originate tone, it returns the appropriate CONNECT result code to your computer. If your modem does not detect the carrier within 30 seconds after answering, it returns NO CARRIER result code and does not answer. You can use the Immediate Answer command (A) to have your modem pick up the phone line. If your telephone rings when auto answer is disabled, your modem returns a RING result code and does not answer. You can use the Immediate Answer command (A) to have your modem pick up the phone line. IMMEDIATE ANSWER (A) You can force your modem to pick put the phone line, even if the phone does not ring. You might use this feature if you called someone on a voice line, then wanted to switch to communicate with their computer or if your telephone rings, and you want your modem to answer. If you are switching from a voice call to a data call, the other party must send AT D ENTER to their modem. AT A ENTER The modem immediately picks up the phone line and sends an answer tone. AUTO ANSWER TIMING PARAMETERS Registers S0, S7, and S9 control the answer mode timing. For more information on register settings, refer to the register document. (smc-12/13/92)