CHAPTER 5. INTERNAL CONTROLS The commands explained in this chapter are of two types. The first group concerns default configurations, for example, writing your own power-on defaults to nonvolatile random access memory (NVRAM). The remaining commands are used to select the modem's local operating characteristics, for a current session or to include in your default configuration. They include result code, echoing, and other options. NOTE: When you change a default setting during a session, the modem retains that setting until you do one of the following. ù Change the setting. ù Issue the ATZ command to reset the modem to its software defaults. If DIP switch 10 is UP, the modem resets to the defaults stored in nonvolatile memory (NVRAM). If DIP switch 10 is DOWN, the modem resets to the factory settings stored in read only memory (ROM). ù Issue the AT&F command to load the modem's factory settings. ù Turn the modem off and power it on again. At power-on, the modem loads either the nonvolatile memory defaults (DIP switch 10 UP) or the factory settings (DIP switch 10 DOWN). SETTING/USING DEFAULTS The modem's read only memory (ROM) permanently stores the modem's factory settings. The inclusion of nonvolatile random access memory (NVRAM) allows you to define your own configuration and write the settings to NVRAM as your power-on defaults. WRITING DEFAULTS TO NVRAM (&W) When you power on the Courier, it loads the settings stored in NVRAM if DIP switch 10 is UP (factory setting). Until you write your own settings to NVRAM, the defaults stored there are the same as the permanent ROM factory settings. You'll find a list of NVRAM options and factory settings in Appendix B. You can also display them by selecting option 5 of the I (inquiry) command: ATI5 If you've sent the modem commands to change settings throughout your session and want to save your current configu- ration, send just the &W command. The current settings are saved. AT&W You may also specify the entire configuration in a single command string that ends with the &W command. The following example sets the modem for the current session and stores the configuration in NVRAM. AT X4 &B1 &H1 M3 &W After sending a configuration to NVRAM, you can change any setting just for the current session, as in the following example. The NVRAM configuration remains intact. ATX7 But if you want the new setting to be a default, write it to NVRAM at the same time, as in the following example. X7 is substituted for the X4 setting stored earlier. AT X7 &W LOADING THE FACTORY DEFAULTS (&F) If DIP switch 10 is DOWN, the factory settings are loaded at power-on instead of the NVRAM defaults. Factory settings for the options that are stored in NVRAM are in Appendix B. If the NVRAM defaults are loaded at power-on (DIP switch 10 UP) and you want to load the factory defaults instead, use the following command: AT&F If NVRAM defaults are loaded, but you want to view a screen listing of factory defaults, first load them (&F), to make them the current settings. Then include the I4 inquiry option to display a listing of the newly current settings, as in the following example. AT&F I4 To restore your NVRAM defaults, use the ATZ command described next. (DIP switch 10 must be UP.) RESET (Z) If you've changed several current settings and want to reset to your power-on defaults, type the following command: ATZ The modem reads its DIP switch settings and resets either to its NVRAM defaults (DIP switch 10 UP) or factory settings (DIP switch 10 DOWN). NOTE: Use the ATZ command also if you've changed the position of DIP switches 2-5, 7 or 9 while the modem is on, so that the modem can read the new setting. The only other way to initiate a new setting for switches 2-5, 7 and 9 is to turn the modem off and on again. STORING TELEPHONE NUMBERS (&Zn=s) The modem stores up to four frequently dialed phone numbers. Write the numbers to NVRAM with the &Zn=s command, where n is position 0 through 3, and s is the phone-number string. The number-string may be up to 36 characters long, including any Dial command options. The following example includes the tone-dial (T) and wait for a second dial tone (W) options of the Dial command. The number is stored at position 0, assumed because there is no n parameter. AT&Z=T9W5551234 The following example stores a long- distance number at the second position. We've added spaces for readability. AT&Z2=1 516 555 1234 The DSn command is used to dial a stored number, as in this example to dial the number stored at position 2: ATDS2 NOTE: Do not include modem settings in the &Z string. If the call requires a special setting, insert it in the command string before the DSn command. In the following example, &M0 (no error control) is inserted before the Dial command: AT&M0 DS2 The previous command establishes &M0 as the current setting. To return to the default error control mode, issue the following command: AT&M4 RESULT CODES Four commands control the result codes that the modem returns to the screen: Vn Numeric/verbal response mode Qn Display/suppress all result codes &An Display/suppress additional result code subsets Xn Result code subset Response Modes (Vn) Result codes are sent to the screen in either words (Verbal Mode) or numbers (Numeric Mode). The Courier is factory set to Verbal mode when it is powered on (DIP switch 2 is UP). Use the Vn command to select verbal or numeric result codes for a current session, independently of the DIP switch setting. At power-on and reset, the modem operates according to the DIP switch setting. The Vn command is not stored in nonvolatile memory as a power- on/reset default. V0 Numeric Mode. Numeric result codes are followed by a Carriage Return but no Line Feed, as in the following example, where a 3 is returned (for NO CARRIER). ATD1234567 becomes 3TD1234567 V1 Verbal Mode. Verbal responses are preceded and followed by a Carriage Return and a Line Feed, as in the following example: ATD1234567 NO CARRIER Quiet Mode (Qn) Enable/suppress the display of result codes. The Courier is shipped with DIP switch 3 DOWN, to display result codes. Use the Qn command to control the display for a current session, independently of the switch setting. At power-on and reset, the modem operates according to the DIP switch setting. The Qn command is not stored in nonvolatile memory as a power- on/reset default. Q0 Result codes are displayed. Q1 Result codes are suppressed (made quiet). Q2 Result codes are suppressed only in Answer mode. Additional Result Code Subsets (&An) Use this command to enable/disable one of the following subsets of error control, modulation or protocol result codes. &A0 ARQ (error control) codes are disabled. This setting does not affect an error-control connection; the modem returns the standard CONNECT messages if result codes are enabled. &A1 ARQ codes are enabled. One of the following results is sent to the screen when a successful error control connection is established. Message 14 is displayed if the modem is set to X0 and the connection is at any rate from 1200 to 14.4K bps. The remaining results indicate the connection rate and require a setting of X1 or higher. 14/CONNECT/ARQ 22/CONNECT 12000/ARQ 15/CONNECT 1200/ARQ 24/CONNECT 7200/ARQ 16/CONNECT 2400/ARQ 26/CONNECT 14400/ARQ 17/CONNECT 9600/ARQ 47/CONNECT 16800/ARQ 19/CONNECT 4800/ARQ &A2 HST/V32 modulation codes are enabled. This option is included for users of HST Dual Standard modems. If your software cannot handle the added modulation information, select &A1 or &A0. 23/CONNECT 9600/HST or 33/CONNECT 9600/V32 27/CONNECT 9600/ARQ/HST or 37/CON NECT 9600/ARQ/V32 28/CONNECT 4800/HST or 38/CONNECT 4800/V32 29/CONNECT 4800/ARQ/HST or 39/CON NECT 4800/ARQ/V32 30/CONNECT 7200/HST or 40/CONNECT 7200/V32 34/CONNECT 7200/ARQ/HST or 44/CON NECT 7200/ARQ/V32 31/CONNECT 12000/HST or 41/CONNECT 12000/V32 32/CONNECT 12000/ARQ/HST or 42/CON NECT 12000/ARQ/V32 35/CONNECT 14400/HST or 45/CONNECT 14400/V32 36/CONNECT 14400/ARQ/HST or 46/CON NECT 14400/ARQ/V32 53/CONNECT 16800/HST 57/CONNECT 16800/ARQ/HST &A3 Protocol codes are enabled. Error control protocols reported are: HST, LAPM, or MNP. When the call is not under one of those protocols (and ARQ is not included in the result code), the modem reports either SYNC, indicating a synchronous connection, or NONE, for no protocol. If the modems are using data compression, the type of compression, V42BIS or MNP5, is added to the result code. In the first of the following examples, the modems negotiated error control for the call (ARQ), used HST modulation, are using HST error control protocol, and are using V.42 bis compression. CONNECT 14400/ARQ/HST/HST/V42BIS [ or MNP5] CONNECT 14400/ARQ/V32/LAPM/V42BIS [ or MNP/MNP5] CONNECT 9600/SYNC CONNECT 2400/ARQ/MNP/MNP5 [or LAPM/V42BIS] CONNECT 2400/NONE NOTE: Although these codes will return numeric identifiers, they are the same numeric identifiers used for &A2 result codes. If the modem is in Numeric Mode (V0) and set to &A3, you will not be able to differentiate between &A2 and &A3 result codes. &A3 result codes may not be compatible with some software. Result Code Sets (Xn) You have eight options, 0 through 7, for selecting the result code subset best suited to your applications. X0 Basic subset, returns the first five codes (0-4) in the following table. X1 Extended subset, codes 0-5, 10, 13 and 18. Default. This set adds rate-specific CONNECT messages to the Basic set. X2-7 These options include the X1 subset and offer advanced call- progress codes and functions. Setting Result Codes X0 X1 X2 X3 X4 X5 X6 X7 0/OK + + + + + + + + 1/CONNECT + + + + + + + + 2/RING + + + + + + + + 3/NO CARRIER + + + + + + + + 4/ERROR + + + + + + + + 5/CONNECT 1200 + + + + + + + 6/NO DIAL TONE + + + + 7/BUSY + + + + + 8/NO ANSWER + + + + + 9/RESERVED 10/CONNECT 2400 + + + + + + + 11/RINGING + + + 12/VOICE + + 13/CONNECT 9600 + + + + + + + 18/CONNECT 4800 + + + + + + + 20/CONNECT 7200 + + + + + + + 21/CONNECT 12000 + + + + + + + 25/CONNECT 14400 + + + + + + + 43/CONNECT 16800 + + + + + + + Functions Adaptive Dialing + + + + + + Wait for 2nd Dial Tone (W) + + + + + Wait for Answer (@) + + + + + Fast Dial + + + + Table 5-1. Result Code Options NOTE: Additional messages indicate an error-control connection and the modulation for a call. See Additional Result Code Subsets (&An), earlier in this chapter. Result Code Meaning 0/OK Command has been executed 1/CONNECT Connection established with another modem; if set to X0, connection may be at 300, 1200, 2400 or 9600 bps; if X1 or higher, connection is at 300 bps 2/RING Incoming ring detected 3/NO CARRIER Carrier detect has failed or carrier has been dropped due to disconnect 4/ERROR Command is invalid 5/CONNECT 1200 Connection established with another modem at 1200 bps 6/NO DIAL TONE Dial tone not detected during the normal 2 seconds, set in Register S6 7/BUSY Busy signal detect; modem hangs up 8/NO ANSWER After waiting 5 seconds for an answer, modem hangs up; returned instead of NO CARRIER when the @ option is used 10/CONNECT 2400 Connection established with another modem at 2400 bps 11/RINGING The modem has dialed; remote phone line is ringing 12/VOICE Voice answer at remote site; modem hangs up 13/CONNECT 9600 Connection established at reported rate. Same meaning for results of 4800 (18), 7200 (20), 12K (21), 14.4K (25) and 16.8K (43, HST only). Adaptive Dialing The modem attempts to use Touch-Tone dialing and, if that doesn't work on the line, reverts to rotary dialing. Wait for Another The modem continues dialing as soon as it detects Dial Tone (W) another dial tone. See the dial options in Chapter 6. Wait for an The modem continues dialing when it detects 5 Answer (@) seconds of silence on the line. See the dial options in Chapter 6. Fast Dial The modem dials immediately on dial-tone detect, instead of waiting the normal 2 seconds set in Register S6. Table 5-2. Result Code Definitions LOCAL ECHO Local echo is the display of what you type at the keyboard and data the Courier transmits to another modem. The En command controls the display of your typed commands, when the modem is in Command Mode. The Fn command applies to when the modem is online to another system. Command Mode Local Echo (En) The En command enables/disables the display of your typed commands. If double characters appear on the screen, both the modem's local echo and your software's local echo are on. The Courier is shipped with DIP switch 4 UP, enabling local echo. The En command controls the local echo for a current session, independently of the switch setting. At power-on and reset, the modem operates according to the DIP switch setting. The En command is not stored in nonvolatile memory as a power- on/reset default. E0 Command Mode echo OFF. The modem does not display keyboard commands. E1 Command Mode echo ON. Online Local Echo (Fn) This command causes the modem to display a copy of the data it is transmitting to another system. Many systems, however, return a copy of received data, which is called a remote echo. If the modem's online echo is ON and there is also remote echoing, double characters appear on the screen. In some microcomputer documentation, the term duplex is applied to local online echoing, although the term is not technically accurate. F0 Online echo ON. Sometimes called half duplex. As the modem transmits data to a remote system, it also sends a copy of the data to the screen. F1 Online echo OFF. Sometimes called full duplex. Default. THE AUDIO MONITOR The modem's speaker enables you to monitor the dial-connect process. There are several ways to make use of this feature. After the Courier dials a number, it waits 60 seconds for a high- pitched answer tone from the other modem, immediately followed by data signals, called a carrier. These signals must occur before a data link is established. At the default X1 setting, if someone answers the phone, or if the line is busy, the modem sends the message NO CARRIER to your screen after 60 seconds. If you listen to the speaker, you can respond immediately instead of waiting for the modem to time out. For example, if you hear someone answering the call, you can pick up the phone, if it's attached to the modem, and talk to the person. Or you can cancel the call by pressing any key on the keyboard. In the same way, you can cancel a call when you hear a busy signal. You can also hear if dialing is proceeding too quickly for the system. Terminate the call (press any key) and retype the Dial command, but insert a comma (,) or a couple of slashes (/), to have the modem pause during the dialing process. SPEAKER CONTROL (Mn) This command disables the speaker entirely or sets the speaker to monitor different segments of the dial-connect sequence. M0 This setting disables the speaker entirely so that you don't hear the modem go off hook, dial, etc. M1 The speaker is ON until Carrier Detect. Default. You can monitor call progress until the Courier detects the remote modem's carrier signals, or until the 60-second timeout and result code display. At Carrier Detect, the modem discon- nects the speaker and data transmission sounds are suppressed. M2 The speaker is ON continuously, including during data transmission. M3 The speaker doesn't go ON until after the last digit is dialed, then goes OFF at Carrier Detect. MODEM CLOCK USAGE (Kn) The modem clock is used as a call- duration timer or as a real-time clock. Used in conjunction with the In (Inquiry) command, the modem returns the duration of the last call in hours, minutes, and seconds or the actual time. K0 Call-Duration Mode. Default. The modem times each call from CONNECT to NO CARRIER, and stores the infor- mation until the next connection or when the modem is reset. At ATI3 , the modem displays the call's duration. If you wish, you can maintain a call log by printing this information after each call. K1 Real-Time Mode. The clock operates as a real-time clock regardless of the presence of a carrier. Set the clock (in military time) by specifying the hour, minutes, and seconds as in the following example, which sets the clock at the real time of 1:30 p.m. ATI3=13:30:00 K1 At ATI3, the modem displays the real time. You'll need to set the clock each time you power on the modem, but the clock is not affected by the reset command, ATZ. TRANSMITTER ENABLE/DISABLE (Cn) If an additional terminal and modem share the phone line for monitoring purposes, the second modem is placed in Receive Only state by disabling its transmitter. Use this feature only at 1200 or 300 bps. C0 Transmitter disabled. Modem is set to Receive Only. C1 Transmitter enabled. Default. BREAK HANDLING (&Yn) This command allows you to send a break to abort data transfer without disconnecting from the phone link. The following options are available. &Y0 Destructive, no Break transmitted: the modem clears the data from its transmit buffer (all data is lost) but does not transmit the Break to the remote modem. &Y1 Destructive, expedited: the modem clears the buffer and immediately sends a Break to the remote modem. Default. &Y2 Nondestructive, expedited: the modem retains data in the transmit buffer, but immediately sends a Break to the remote modem. &Y3 Nondestructive, unexpedited (send Break in sequence): the modem transmits any buffer data received before the Break, sends the Break, and then sends any subsequent input from the DTE. NOTE: If the call is under MNP5 data compression, destructive Breaks cause both modems to reset their data compression tables. When transmission resumes, the modems build new tables, and the result is lower than normal throughput. S-REGISTERS The S-Registers are used to set various timing parameters, redefinition of selected ASCII characters, and other configuration options. The defaults reflect typical requirements. A detailed summary of the S-register functions is in Appendix B. A less detailed summary is in the Quick- Reference card.