COURIER HST APPENDIX B SUMMARIES AND TABLES CONTENTS B-1 The RS-232C Interface, with Pin Definitions B-2 Front End Indicators B-3 DIP Switch Summary B-4 Default Settings B-5 S-Register Summary B-6 ASCII Chart B-1 COURIER HST APPENDIX B-1 THE RS-232C INTERFACE, WITH PIN DEFINITIONS DESCRIPTION The RS-232C interface (often referred to without the C) is a standard developed by the Electronic Industries Association (EIA). It defines the signals and voltages used when data is exchanged between a computer or terminal and a modem or serial printer. Data is transmitted between the devices via a cable with 25-pin, 9-pin or custom-built connectors. PIN ASSIGNMENTS The entire standard covers many more functions than are used in most data communications applications. Pin assignments are factory set in the Courier 2400e to match the standard DB-25 assignments in the following table. DB-9 connectors at the computer/terminal end of the cable should be wired to reflect the pin assingments in the DB-9 column. RS-232C INTERFACE PIN DEFINITIONS DB-25 DB-9 Circuit Function Signal Flow 2 3 BA Transmitted Data Terminal ® Modem 3 2 BB Received Data Terminal ¬ Modem 4 7 CA Request to Send Terminal ® Modem 5 8 CB Clear to Send Terminal ¬ Modem 6 6 CC Data Set Ready Terminal ¬ Modem 7 5 AB Signal Ground Terminal « Modem 8 1 CF Carrier Detect Terminal ¬ Modem 12 -- SCF Speed Indicate Terminal ¬ Modem 20 4 CD Data Terminal Ready Terminal ® Modem 22 9 CE Ring Indicate Terminal ¬ Modem MINIMUM REQUIREMENTS Some computer/terminal equipment supports only a few of the RS- 232C signal functions set in the Courier. The minimum required for the modem to operate are as follows: DB-25 DB-9 Pin Pin Function 2 3 Transmitted Data 3 2 Received Data 7 5 Signal Ground 20 4 Data Terminal Ready* B-2 COURIER HST * Required only if you have set the Data Terminal Ready (DTR) Override switch (DIP switch 1) OFF (UP). If your computer and software support Clear to Send and you wish to use Transmit Data hardware flow control (&H1), Pin 5 (DB-25) or Pin 8 (DB-9) is required. If your computer and software support Request to Send and you wish to use Received Data hardware flow control (&R2), Pin 4 (DB-25) or Pin 7 (DB-9) is required. B-3 COURIER HST APPENDIX B-2 FRONT END INDICATORS Symbol Meaning Status HS High Speed 9600-bps calls only: ON during call progress, after completion of dialing; OFF during link negotiations at 2400 bps; ON during connection. Remains ON after disconnect until next call is originated or answered. AA Auto Answer/ Answer Mode only: ON when your modem is Answer in Auto Answer Mode, and when answering a call; goes OFF if the channel is rever sed and your modem transmits at 450 bps. Also goes off when the modem originates a call. CD Carrier Detect ON when the CD override (DIP switch 6) is ON (DOWN). ON if DIP switch 6 is UP and the Courier receives a valid data signal (carrier) from a remote modem, indicating that data transmission is possible. OH Off Hook ON when the Courier takes control of the phone line to establish a data link. RD Received Data Flashes when a data bit is received by the Courier from the phone line, or when the modem is sending result codes to the terminal or computer. SD Send Data Flashes when a data bit is sent to the Courier by the terminal or computer. TR Terminal Ready ON when the DTR override (DIP switch 1) is ON (DOWN). ON if DIP switch 1 is UP and the modem receives a Data Terminal Ready signal from the terminal or computer via the RS-232C interface. MR Modem Ready/ ON when the Courier is powered on. Power Flashes when the modems retrain, inclu ding online fallback to 7200 or 4800 bps. B-4 COURIER HST RS Request to ON when the Courier is powered on if Send your computer supports RTS on the RS- 232C interface. OFF if the Courier is set to &R2 (Received Data hardware flow control) and the computer lowers RTS. CS Clear to Send ON until the modem lowers CTS on the RS- 232C interface when Transmit Data hardware flow control is enabled (&H1, &H3). ARQ Error Control Automatic Repeat Request. ON when the Courier is set to &M4 or &M5 and successfully connects with another modem under error control. AL Analog ON when the modem is in Analog Loopback Loopback Self-Test Mode. B-5 COURIER HST APPENDIX B-3 DIP SWITCH SUMMARY PURPOSE The Courier's DIP switches, located at the rear of the modem, are for adapting the modem to your equipment and personal requirements. You may also want to experiment and review your computer or terminal documentation as necessary. Some users are able to move a single switch with a finger tip. If this doesn't work for you, use a toothpick or other small instrument. OPERATIONS The DIP switch settings are power-on defaults, read by the Courier when it is turned on. If changed when the modem is on, switches 2-5 and 9 require the ATZ (software reset) command to initiate the new settings. The remaining (hardware) switches are automatically operative when set UP or DOWN. DIP SWITCHES: UP = OFF (OPEN), DOWN = ON (CLOSED) Factory Switch Setting Function 1 DOWN Data Terminal Ready (DTR) Operations UP Normal DTR operations; computer must provide DTR signal for modem to accept commands; dropping DTR terminates a call DOWN DTR always ON (Override) 2 UP Verbal/Numeric Result Codes UP Verbal (word) messages DOWN Numeric codes 3 DOWN Result Code Display UP Quiet Mode, no display DOWN Result codes displayed 4 UP Command Mode Local Echo UP Keyboard commands displayed DOWN Display of commands suppressed 5 DOWN Auto Answer UP Modem answers on first ring DOWN Auto Answer suppressed B-6 COURIER HST 6 DOWN Carrier Detect (CD) Operations UP Courier sends CD signal when it connects with another modem, drops CD on disconnect DOWN CD always ON (Override) 7 UP Single/Multiple Phone Installation UP Single phone line connection (RJ11 jack) DOWN Multiple phone installations (RJ12 or RJ13 jack); shorts A/A1 to notify other devices when modem goes off hook and line is busy 8 DOWN Command Set Recognition UP Rrecognition disabled (Dumb Mode) DOWN Recognition enabled (Smart Mode) 9 DOWN Escape Code (+++) Response UP Modem hangs up, returns to Command Mode, sends NO CARRIER result DOWN Modem maintains connection, returns to Command Mode, sends OK result 10 UP Power-on and ATZ Reset Software Defaults UP Load from NRAM DOWN Load factory settings from ROM Quad UP RS-232C Transmitted/Received Data Pin Switch Assignments UP Normal assignments: see Appendix B-1 DOWN Reverse assignments The need to change this setting is rare. Carefully review your computer or terminal documentation before turning this switch ON. B-7 COURIER HST APPENDIX B-4 DEFAULT SETTINGS USER-PROGRAMMABLE DEFAULTS You can create your own default configuration and store it in nonvolatile random access memory (NRAM) using the &W command described in Chapter 5. Your defaults are then loaded into random access memory (RAM) as long as DIP switch 10 is UP when you power on the modem. To view your NRAM settings at any time, use the ATI5 command. The following table lists the options stored in NRAM. If DIP switch 10 is DOWN at power on, the factory settings listed in the table are loaded instead. The first time the modem is turned on, the NRAM settings are the same as the factory settings. B-8 COURIER HST NRAM Options Factory Setting Normal/error control modes &M4 Normal/ARQ Data compression &K1 Auto enable/disable Error-control result codes &A1 Enabled Transmit data flow control &H0 Disabled Received data software flow control&I0 Disabled Received data hardware flow control&R1 Ignore RTS DTE rate select &B0 Follow connection rate Link rate select &N0 Variable link operations Data Set Ready (DSR) signal &S0 Override Stored telephone number &Z0-3=0 Blank Tone/Pulse dialing P Pulse dial Online local echo F1 Echo OFF Speaker control M1 ON during dial through connect Result code sets X1 Extended Pulse dial make/break ratio &P0 N. American U.S./CCITT answer tone B1 N. American Guard tone &G0 Break handling &Y1 Clear buffer, send Break immediately Word length 7* Parity 1* Even parity *Detected from AT command; determined by terminal/software setting. NRAM S-Register Option Factory Setting Escape code character, ASCII decimal S2=43 Carriage Return character, ASCII decimal S3=13 Line Feed character, ASCII decimal S4=10 Backspace character, ASCII decimal S5=8 Dial wait-time, sec. S6=2 Carrier wait-time, sec. S7=30 Dial pause/re-execute time, sec. S8=2 Carrier Detect time, 1/10th sec. S9=6 Carrier loss wait-time, 1/10th sec. S10=7 Touch-Tone duration, spacing, msec. S11=70 Escape code guard time, 1/50th sec. S12=50 Bit-mapped functions, S-Register 13 S13=0 Bit-mapped functions, S-Register 15 S15=0 Inactivity/hang up timer, S-register 19 S19=0 B-9 COURIER HST Received break length, 10-msec. units S21=10 XON character, ASCII decimal S22=17 XOFF character, ASCII decimal S23=19 B-10 COURIER HST APPENDIX B-5 S-REGISTER SUMMARY USAGE The default values are those users typically require. Change the settings with the ATSr=n command, where r is the register and n is a decimal value from 0-255: ATS13=8 The modem does not perform a value-range check. Some values may not work with some equipment, and you'll have to readjust the settings. To display the contents of a register, use ATSr? as in this example: ATS20? Register Default Function S0 See DIPSets the number of rings on which to answer Switch 5 when in Auto Answer Mode. Default = 1, equivalent of DIP switch 5 UP. S0=0 or DIP switch 5 DOWN (factory setting) suppresses Auto Answer. S1 0 Counts and stores the number of rings from an incoming call. S2 43 Stores the ASCII decimal code for the escape code character. Default character is "+". A value of 128-255 disables the escape code. S3 13 Stores the ASCII decimal code for the Carriage Return character. S4 10 Stores the ASCII decimal code for the Line Feed character. S5 8 Stores the ASCII decimal code for the Backspace character. A value of 128-255 disables the Backspace key's delete function. S6 2 Sets the number of seconds the modem waits before dialing. If set to X2, X4, X6, or X7, the modem ignores this register and dials as soon as it detects a dial tone (fast dials). B-11 COURIER HST S7 30Sets the number of seconds the modem waits for a carrier. May be set for much longer duration if, for example, the modem is originating an international connection. S8 2 Sets the duration, in seconds, for the pause (,) option in the Dial command and the pause between command re- executions (> and A> commands). S9 6 Sets the required duration, in tenths of a second, of the remote modem's carrier signal before recognition by the Courier (Carrier Detect Time). S10 7 Sets the duration, in tenths of a second, that the modem waits after loss of carrier before hanging up. S11 70Sets the duration and spacing, in milliseconds, of dialed Touch-Tones. S12 50Sets the duration, in fiftieths of a second, of the guard time for the escape code sequence. S13 0 Bit-mapped register. Select the bit(s) you want on, and set S13 to the total of the values in the Value column. For example, ATS13=20 enables bits 2 (value = 4) and 4 (value = 16). Bit Value Result 0 1 Reset on dropping of DTR 1 2 Reverse normal Auto Answer operation: on incoming RING, enter Originate Mode and look for Answer tone 2 4 Disable 250 msec. pause before result code display 3 8 On DTR signal, Auto Dial number stored in NRAM at position 0 4 16 At power on/reset, Auto Dial number stored in NRAM at position 0 5 32 Reserved 6 64 Disable MNP Level 3 (used for testing Level 2) 7 128 Watchdog hardware reset, same as power on (used in factory testing) S14 Reserved. S15 0 Bit-mapped register. See instructions for S13, above. B-12 COURIER HST Bit Value Result 0 1 Disable the modem's extra high- frequency equalization if it causes problems on shorter-link calls 1 2 Disable 7200/4800 bps online fallback 2 4 Disable 450-bps back channel, force 300-bps back channel 3 8 Reset non-ARQ mode Transmit buffer from 1.5k bytes to 128 bytes* 4 16 Disable MNP Level 4; retransmitting the larger Level 4 data blocks may be a problem if you expect a great number of errors during a call 5 32 Set Del key to act as Backspace key; provided for specialized applications. May cause software incompatibility in standard applications. 6 64 Some earlier 2400-bps MNP modems, not made by USRobotics or Microcom, were not fully compatible with the MNP protocol. If you have difficulty making a successful 2400-bps MNP connection with a remote MNP modem, it may be because of this incompatibility. Set S15 to 64 and try again to make the connection. 7 128 Enable Interbridge network compatibility * The default 1.5k byte non-ARQ buffer allows data transfer with X- and YMODEM-type file transfer protocols without using error control. The 128-byte option allows remote users with slower modems to stop data you're transmitting from scrolling off their screens. When remote users send your computer an XOFF (Ctrl-S) and you stop transmitting, the data in transit from your modem's buffer doesn't exceed the size of their screen. B-13 COURIER HST S16 0 Modem self- test. See Appendix E-6 for test procedures. 0 Data Mode (no testing) 1 Analog Loopback 2 Dial Test 4 Test Pattern 5 Analog Loopback with Test Pattern S17 0 Stores the reason for a received ARQ Link Disconnect. May be requested by Technical Support if you're having a problem connecting in ARQ mode with another ARQ-mode modem. At ATS17?, the modem returns one of the following codes. 1 Received data unit other than link request 2 Incompatible protocol level (3, 2, 1) 3 Unknown parameters in link request 4 Remote modem retry timeout (Max. 12 tries) 5 Inactivity timeout (See S19) 6 Destination user not found 254 Peer protocol error 255 User-initiated disconnect S18 Reserved. S19 0 Sets the duration, in minutes, for the Inactivity Timer. The timer is activated when there is no activity on the phone line. At the timeout the Courier hangs up. S20 0 Stores the reason for the NO CARRIER result code. At ATS20? the modem returns one of the following codes: 0 Key press abort 1 DTR dropped 2 Escape code (+++) issued 3 Loss of Carrier 4 Inactivity timeout 5 Automatic hangup with ARQ incompatibility (&M5 Mode) 6 ARQ Retry timeout (Max. 12 tries) 7 ARQ Received Link Disconnect (See S17) S21 10 Sets, in 10- millisecond units, the length of Breaks sent from the modem to the local terminal. B-14 COURIER HST S22 17 Stores the ASCII decimal code for the XON character. S23 19 Stores the ASCII decimal code for the XOFF character. B-15 COURIER HST APPENDIX B-6 ASCII CHART B-16