LineLink S Registers This is an extract from the Hayes Technical Reference Manual (TRM20.ZIP) and the Supra FaxModem Bible (FMB11.LHA) Some of these may be incorrect for the LineLink. S Registers appearing in LineLink Profile: S00 S02 S03 S04 S05 S06 S07 S08 S09 S10 S11 S12 S14 S16 S18 S21 S22 S23 S25 S26 S27 S36 S37 S38 S46 S48 S49 S50 S63 S82 Hayes/Supra S-Register Descriptions S0 Ring to Answer After S0 sets the ring number on which the modem automatically answers a call when auto-answer mode is selected. S0=0, the factory setting, disables auto-answer. S1 Ring Count When the modem is in the command state and set for auto-answer (S0>0), the modem automatically tracks the number of times the phone rings, incrementing and writing the value in S1. The value reverts to 0 if no ring occurs for 8 seconds. Once a connection is made, the modem resets the value of S1 to 0. Note that two short ring bursts within a ring cycle are counted as two rings. S2 Ecape Sequence Character S2 holds the ASCII value of the escape sequence character. The factory- set value is ASCII 43, the plus sign (+). The value for this register can be set to any ASCII value between 0 and 127. Setting S2 to a value greater than 127 disables the escape sequence, preventing the modem from returning to the command state and disabling command recognition. S3 Carriage Return Character S3 holds the ASCII value of the line terminating character. The factory- set value is ASCII 13 - carriage return () - the range for the register is 0-127. This character is used both as the command line terminator and the result code terminator. S4 Line Feed Character S4 holds the ASCII value of the line feed character. The factory setting is 10; the range is 0-127. S5 Backspace Character S5 holds the ASCII value of the backspace character. The factory-set value is ASCII 08; the range for the register is 0-32, 127. This character moves the cursor left, removing the previous character. As this value actually represents the combined operation of three characters (a backspace, a space, and another backspace), the time allotted to process the backspace character must not be any less than the time required by the modem to transmit three characters. For this reason, a repeat-key function may not operate properly on backspaces. S6 Wait Before Blind Dialing S6 determines how long the modem waits after going off-hook before it dials. This delay allows time for the central telephone office to detect the off-hook condition of the line and apply dial tone. This wait time only applies to the first dial tone. S6 is used only if X0, X1, or X3 is selected. Selecting X2 or X4 enables dial tone (call progress) detection and disables blind dialing, thus making the setting of S6 irrelevant. The value of this register can be set for any number from 4 through 7 seconds. This feature allows you to increase the time delay if you have difficulty obtaining dial tone within 4 seconds. Note: The Wait Before Dialing call progress monitoring feature (W dial modifers) applies only to detection of a second dial tone and is independent of any S-register setting. S7 Wait for Carrier after Dialing S7 determines the modem's time delay between dialing and responding to an incoming carrier signal after initial connection. If the modem does not detect a carrier within this time, the modem hangs up and returns the NO CARRIER result code. If the modem detects a carrier within the specified time, it goes on line. S8 Duration of Delay for Comma Dial Modifier S8 determines the duration of the delay generated by the comma (,) dial modifier. S9 Carrier Detect Response Time S9 determines how many seconds a carrier signal must be present for the modem to recognize it and issue a carrier detect. The value for the register is measured in tenths of a second. The factory setting is 6 (0.6 second); the range is 1 (0.1 second) to 255 (25.5 seconds). Note: The S9 value affects the time required to recognize the presence of carrier only if X3 or X4 is selected. The modem also ignores the value in register S9 when operating in half-duplex synchronous or asynchronous mode. S10 Delay Between Lost Carrier and Hang Up S10 specifies the time between loss of remote carrier and local modem disconnect. The delay permits the carrier to disappear momentarily without causing the modem to hang up. The value for the register is measured in tenths of a second. The range for most modems is 1 (0.1 second) to 255 (25.5 seconds). The modem recognizes a carrier after the period of time specified in S9. Therefore, if the value of S10 is less than that set for S9, even a momentary loss of carrier will cause the modem to disconnect. Setting the register to 255 causes the modem to ignore actual carrier status and assume a carrier is always present. When operating in half-duplex synchronous mode, S10 specifies the maximum time (in seconds) that a carrier may be continuously present or absent before causing the modem to disconnect. S11 Multi-Frequency Tone Duration S11 determines the duration and spacing of tones in multi-frequency tone dialing. The value in this register has no effect on the speed of pulse dialing. S12 Escape Sequence Guard Time S12 holds the value of the delay required prior to and following the escape sequence. The guard time also dictates how quickly the escape sequence characters must be entered, since the interval between entry of each of the three characters must be of shorter duration than that specified for the guard time. If guard time is set to 0, timing is not a factor. S14 Bit Mapped Option Status Codes Bit(Dec) 0 (1) Reserved 1 (2) Command echo (En) 0 Disabled (E0) 1 Enabled (E1 default) 2 (4) Quiet Mode (Qn) 0 Send result codes (Q0 default) 1 No result codes (Q1) 3 (8) Result codes (Vn) 0 Numeric (V0) 1 Verbose (V1 default) 4 (16) Reserved 5 (32) Dial Mode 0 Tone (T default) 1 Pulse (P) 6 (64) Reserved 7 (128) Carrier Mode 0 Answer 1 Originate S16 Diagnostic Test Mode setting -Bit Mapped (default 0) 0 &T1 0 Disable 1 Enable 1 Not Used 2 &T3 0 Disable 1 Enable 3 &T4/&T5 0 Off 1 In progress 4 &T6 0 Disable 1 Enable 5 &T7 0 Disable 1 Enable 6 &T8 0 Disable 1 Enable 7 Not Used S18 Modem Test Timer S18 establishes the duration of the modem's diagnostic tests. When a test is active for a length of time equal to the value chosen for this register, the modem automatically terminates the test. A setting of zero (0) disables the test timer (factory setting). The range for this register is 0-255 seconds. S21 Bit Mapped Option Status Codes Bit(Dec) 0 (1) Set by &Jn command but ignored otherwise 0 &J0 (default) 1 &J1 1 (2) Reserved 2 (4) CTS Mode (&Rn) 0 CTS always on (&R0) 1 CTS follows RTS (&R1 default) 3 (8) & 4 (16) DTR behavior (&Dn) 0,0 &D0 (default) 1,0 &D1 0,1 &D2 1,1 &D3 5 (32) DCD (RLSD) behavior (&Cn) 0 &C0 (Default) 1 &C1 6 (64) DSR behavior (&Sn) 0 &S0 (Default) 1 &S1 7 (128) Long space diconnect (Yn) 0 Y0 (Default) 1 Y1 S22 Bit Mapped Option Status Codes Bit(Dec) 0 (1) & 1 (2) Speaker volume (Ln) 0,0 Low (L0) 1,0 Low (L1) 0,1 Medium (L2 default) 1,1 High (L3) 2 (4) & 3 (8) Speaker control (Mn) 0,0 Disabled (M0) 1,0 On until carrier (M1 default) 0,1 ON Always (M2) 1,1 On during handshake (M3) 4 (16), 5 (32), & 6 (64) Dialing Mode / Result Codes (Xn) 0,0,0 X0 1,0,0 Reserved 0,1,0 Reserved 1,1,0 Reserved 0,0,1 X1 1,0,1 X2 0,1,1 X3 1,1,1 X4 (Default) 7 (128) Reserved S23 Bit Mapped Option Status Codes Bit(Dec) 0 (1) Grant RDL 0 RDL not allowed (&T5) 1 RDL allowed (&T4 default) 1 (2), 2 (4), & 3 (8) Assumed DTE Rate 0,0,0 0-300 bps 1,0,0 600 bps 0,1,0 1200 bps 1,1,0 2400 bps (Default) 0,0,1 4800 bps 1,0,1 9600 bps 0,1,1 19200 bps 1,1,1 Reserved 4 (16) & 5 (32) Assumed DTE parity 0,0 Even 1,0 Reserved 0,1 Odd 1,1 None (default) 6 (64) & 7 (128) Guard tone (&Gn) 0,0 None (&G0 Default) 1,0 550 Hz (&G1) 0,1 1800 Hz (&G2) 1,1 Reserved S25 DTR Detection S25 serves two purposes. When the modem is operating in synchronous mode 4, the value assigned to S25 specifies the length of time the modem waits after a connection has been made, before examining the DTR circuit. This allows the modem to ignore an on-to-off transition of DTR and gives the user sufficient time to disconnect the modem from the asynchronous terminal and attach it to a synchronous terminal, without forcing the modem back to the asynchronous command state. During this time, the value of S25 is read in full seconds (e.g., the factory-set value of 5 equals 5 seconds, instead of 0.05 seconds). In all other modes, and after call establishment in synchronous mode 4, the value is read in 1/100 seconds. In any mode, a change in DTR (on or off) that persists for a period shorter than the value held in S25 is ignored by the modem while it is on-line. The range of values for S25 is 0-255. S26 RTS to CTS Interval S26 is used to specify the interval to delay before turning on CTS after an off-to-on transition of RTS. This value takes effect when the &R0 command option has been selected. This setting applies to synchronous modes 1, 2, and 3 only. The factory-set value is 1 (.01 seconds) with a range of 0-255. S27 Bit Mapped Option Status 0100 1001 Bit(Dec) 0 (1), 1 (2), 3 (8) Sync/Async Mode Selection (&Mn/&Qn) 0,0,0 &M0/&Q0 1,0,0 &M1/&Q1 0,1,0 &M2/&Q2 1,1,0 &M3/&Q3 0,0,1 &Q4 1,0,1 &Q5 (Default) 0,1,1 &Q6 2 (4) Leased line control (&Ln) 0 Dial-up line (&L0 default) 1 Leased line (&L1) 4 (16) & 5 (32) Internal Sync clock select (&Xn) 0,0 Internal (&X0 default) 1,0 External (&X1) 0,1 Slave (&X2) 6 (64) CCITT/Bell Mode (Bn) 0 CCITT (B0) 1 Bell (B1 US default) 7 (128) Reserved S36 Negotiation Failure Treatment When an attempt to make an error-control connection fails, the modem reads this register to determine whether to terminate the connection, make an asynchronous connection (otherwise selected with &Q0), or make an asynchronous connection with ASB (otherwise selected with &Q6). This register is referenced only when the error-control mode has been selected with the &Q5 command (factory setting) and this communication mode cannot be negotiated. #------------------------------------------------------------------------ 0 Hang up. 1 Attempt a standard asynchronous connection (&Q0). 3 Attempt an asynchronous connection using automatic speed buffering (&Q6). 4 Attempt a V.42 Alternative Protocol connection (MNP compatible); if negotiation fails, hang up. 5 Attempt a V.42 Alternative Protocol connection (MNP compatible); if negotiation fails, attempt a standard asynchronous connection. 6 Attempt a V.42 Alternative Protocol connection (MNP compatible); if negotiation fails, hang up. 7 Attempt a V.42 Alternative Protocol connection (MNP compatible); if negotiation fails, attempt an asynchronous connection using automatic speed buffering (ASB). #------------------------------------------------------------------------ In asynchronous mode, the CONNECT XXXX message will be returned with a successful connection. This message indicates the speed of the connection, which is also the speed of data transmitted from computer to modem. Note: The selected fallback option can be initiated immediately with S48. For example, a connection attempt using the Alternative Protocol can be forced by setting S48=128 and S36=5 or 7. The following table shows the order in which the bits of S36 are evaluated: (Remember, these steps only occur after the S46/S48 selections have failed to make a LAPBased error-controlled connection in &Q5 mode.) #--------------------------------------------------------------------------- S36 Bit 7-3=0 reserved First Bit 2 (4) If set, means try MNP protocol; reset means don't use MNP. Third Bit 1 (2) If set, means fall back to ASB; reset means direct async. Second Bit 0 (1) If set, means fall back based on Bit 1; reset means hang up. #------------------------------------------------------------------------ Also see Appendix D,"Establishing the Desired Connection and Fallback Strategy." S37 Desired DCE Line Speed The modem attempts to connect with a remote modem at the highest supported DCE speed that does not exceed the value specified by this register. If S37 is set to a speed higher than that supported by the modem, it will attempt to connect at its highest capability. Note that this is the speed of modems across the telephone line, not the speed at which the modem communicates with the attached DTE. #--------------------------------------------------------------------------- 0 Attempt to connect at highest line speed that does not exceed the speed of last AT command issued. 1 Attempt to connect at 75 bps 2 Attempt to connect at 110 bps 3 Attempt to connect at 300 bps 4 Reserved 5 Attempt to connect at 1200 bps 6 Attempt to connect at 2400 bps 7 Attempt to connect at 4800 bps 8 Attempt to connect at 7200 bps 9 Attempt to connect at 9600 bps 10 Attempt to connect at 12000 bps 11 Attempt to connect at 14400 bps #---------------------------------------------------------------------------- S38 Delay Before Forced Hang up S38 specifies the delay between the modem's receipt of the command to hang up (or on-to-off transition of DTR if the modem is configured to follow the signal) and the disconnect operation. This register is useful for error-control communications to ensure that data in the modem buffers is sent before the connection is terminated. The factory setting is 20 (seconds). If this register is set between 0 and 254, the modem will wait that number of seconds for the remote modem to acknowledge receipt of all data in buffers before hanging up. If this timeout occurs before all data can be sent, the NO CARRIER (3) result code will be sent to indicate that data has been lost. If all data is transmitted prior to the timeout, the response to the H0 command will be OK. If S38 is set to 255, the modem does not timeout, and continues to attempt to deliver data in buffers until the connection is lost, or the data is delivered. S46 Error-control Protocol Selection S46 specifies the error-control method used for subsequent connections. Because the factory setting will be a protocol for point-to-point communications, other connections, such as the X.25 protocol must be enabled by setting S46. Feature negotiation enables two communicating modems to identify the common protocols, and chooses one based on the user-configuration for the communication session. For example, if an ULTRA product is configured to use the X.25 protocol, but connects with a V-series product without X.25 capability, an error-control protocol is automatically selected because both modems support it. However, if a ULTRA product with X.25 connects with another ULTRA product with X.25, both can use X.25 protocol if configured to do so (S46=6). When attempting a connection to a packet-switched network, automatic feature negotiation is usually disabled because unless an X.25 connection can be made, further network connections cannot be made. To disable automatic feature negotiation and make an X.25 connection or hang up, set S46=134. The options for this register are described below: #------------------------------------------------------------------------ 0 Either LAPM or fallback to LAPB 1 LAPB only 2 LAPM or fallback to LAPB; use data compression* 3 LAPB with data compression* 6 X.25 or fallback to LAPB; use data compression* 134 X.25 136 LAPM only 138 LAPM with data compression* #------------------------------------------------------------------------ * Note: The technique negotiated is determined by capabilities and configuration of both modems. V.42bis is attempted first, then Hayes Adaptive Data Compression. If neither method is supported by both modems, or if either modem has compression disabled, no compression will be used. S48 Enabling/Disabling Feature Negotiation S48 selects how feature negotiation is used when making connections with the remote system. The negotiation process can be tailored to suit a connection, or bypassed altogether. For example, when the capabilities of the remote modem are known, negotiation is unnecessary. The factory setting is 7, negotiation enabled. With feature negotiation disabled, the modem assumes that the remote modem is configured the same as itself, and proceeds to activate the error-control protocol specified by the S46 (protocol options) setting. Use 128 when calling a packet-switched network that does not support feature negotiation. #------------------------------------------------------------------------ 0 Negotiation disabled; presume the remote modem is configured for and has the capabilities necessary for the connection selected with S46. 3 Negotiation enabled, but originating modem remains silent during detection phase. For connections with MNP modems; however, this setting defeats the negotiation sequence with other V.42 modems. 7 Negotiation enabled. 128 Negotiation disabled; forces fallback options specified in S36 to be taken immediately. #------------------------------------------------------------------------ S49 ASB buffer size lower limit S49 sets the lower limit of the modem's buffer when communicating in asynchronous mode with ASB. The range of this register is 1-249. The factory setting is 8 bytes. S50 ASB buffer size upper limit S50 sets the upper limit of the modem's buffer when communicating in asynchronous mode with ASB. The range of this register is 2-250 bytes. The factory setting is 16 bytes. S63 Private Circuit (Leased Line) Carrier Level Adjustment S63 selects the carrier power level in dBm for leased line operation. This register specifies a nominal carrier level value. The range for this register is 0-15 (0 dBm to -15 dBm). The factory setting is 0. Note that for those modems supporting leased line operation, carrier level (if adjustable) may be set by other means. Please refer to the modem's installation information for details. S82 Break Signaling Technique S82 selects a method of break signal handling for V.42 communications: in sequence, expedited, and destructive. Break signals provide a way for you to get the attention of the remote host. The break type used depends on your application. The values for S82 are: #------------------------------------------------------------------------ 3 Expedited signaling regardless of its sequence in data sent and received; data integrity maintained. 7 Destructive signaling regardless of its sequence in data sent and received; data in process at time is destroyed. 128 In sequence signaling as data is sent and received; data integrity maintained ahead of and after break. #------------------------------------------------------------------------ AT commands: The AT commands are poorly documented also, some being missing, some incorrect. Some are even hidden. SC1=000 - no idea what this does ===Note that the Linelink does not have register S95=== W - Negotiation Progress Message Selection The W command works in conjunction with S95 (where supported) to determine which result codes will be used to describe the type of connection and protocol, etc., that resulted from handshaking and negotiation. The W command supports extended result codes in addition to the CONNECT result code. When the modem is operated in error-control mode (&Q5 is in effect), the W command and S95 together allow the user to select these additional result codes: CARRIER PROTOCOL AUTOSTREAM COMPRESSION CONNECT Any result codes enabled by the W command and S95 will be generated in the order indicated above. If AutoStream is not being used, no AUTOSTREAM result code is returned. Result codes not enabled when the W command option is in effect may be turned on by setting certain bits in S95. The W command options below are available when S95 is configured for any setting other than the factory-setting of 0. #------------------------------------------------------------------------ W0 CONNECT result code reports DTE speed, and if S95=0, then disable all extended result codes. W1 CONNECT result code reports DTE speed, and if S95=0, then enable the CARRIER and PROTOCOL extended result codes. W2 CONNECT result code reports DCE speed, and if S95=0, then disable all extended result codes. #------------------------------------------------------------------------ Refer to the S95 bit map description in the next section. Note that selecting W0 and setting S95=12 is the same as selecting W1; and that selecting W0 and setting S95=1 is the same as selecting W2. S95 cannot be configured to force W2 to report DTE speed in the CONNECT result code; there is no setting of S95 that will force W1 not to produce the CARRIER and PROTOCOL result codes. S95 extends the functionality of the W command. The W command with S95=0 (factory setting) maintains backwards compatibility with previous Hayes Products. However, selecting W0 and setting S95 as required allows you to tailor result code characteristics to your own requirements. ===Note that the Linklink modem does not have register S95=== X - Call Progress Options The X command enables tone detection options used in the dialing process. As these functions are enabled and disabled, the modem's result code reporting is also affected. For this reason, this command is frequently used to control the modem's range of responses; however, its primary function is that of controlling the modem's call response capabilities. Some call progress options are not available in certain countries due to PTT regulations. Refer to the user documentation supplied with your modem for applicable X commands and result codes. Result code definitions are provided in the next section. #------------------------------------------------------------------------ X0 Busy and dial tone detection are disabled. Only result codes 0-4 are enabled. Only the CONNECT result code is permitted, but with no indication of the telephone line speed. This setting overrides any other result code selections made with the W command and S95. X1 Busy and dial tone detection are disabled. Result codes 0-5 are enabled and line speed reporting with CONNECT XXXX messages. W command options and S95 are enabled. X2 Busy detection is disabled. Dial tone detection is enabled. Result codes 0-6 are enabled and line speed reporting with CONNECT XXXX messages. W command options and S95 are enabled. X3 Busy detection is enabled. Dial tone detection is disabled. Result codes 0-5 and 7 are enabled and line speed reporting with CONNECT XXXX messages. W command options and S95 are enabled. X4 Busy and dial tone detection are enabled. Result codes 0-7 are enabled and line speed reporting with CONNECT XXXX messages. W command options and S95 enabled. #---------------------------------------------------------------------- The @ and W dial modifier result codes are not affected by the X command. The @ dial modifier enables result codes 8 (NO ANSWER) and 7 (BUSY) each time it occurs in the dial string. The W dial modifier enables result codes 6 (NO DIALTONE) and 7 (BUSY) each time it occurs in the dial string. ======================================================================== And here is a totally separate document about the Linelink S Registers, from the manufacturer of the modem. ======================================================================== LineLink 144e S-Register Settings --------------------------------- The LineLink 144e modem (A Prometheus product) has an incomplete description of the available modem commands. Specifically, the manual is missing the options for S register settings. Included here is the complete list, obtained directly from Prometheus. [NOTES] - Here at Penn State, we are experiencing problems between the LineLink and out Telebit T3000 modems. For reasons yet determined we cannot establish LAPM and/or V.42bis connections, and the LineLink falls back to MNP(1-4, 5). We do not want MNP to be used with the PPP dialup service and users should enter the following command to ensure that MNP does not get enabled: AT&F3\N5%C0 We are currently looking into a solution so that users of the LineLink will be able to participate in the benefits of LAPM/V.42bis connections with the Telebit T3000's. This file will be updated when solutions are available. - If you have questions... you can forward them to me at: murchison@psu.edu or you can contact a human at prometheus at the address: prometh@teleport.com I suggest you contact me first if the problem is PSU-Specific, since we may already have a solution. Calling Prometheus tech support is currently not an option because the number was incorrectly listed as Compaq's help line and Prometheus is getting hammered with calls from Compaq users. S Register Specifics -------------------- S0 Auto-answer Range Default 0-255 rings 0 This register determines the number to rings the modem will count before automatically answering a call. A value of 0 will prevent the modem from answering. Values from 1 thru 255 are the number of rings the modem will count before answering. The default value is 0. S1 Count Incoming Rings Range Default 0-255 rings 43 This register counts the number of incoming rings. When the value in this register equals the value in Register S0, the modem answers. This register resets approximately 8 seconds after the last ring. S2 Escape Character Range Default 0-127 ASCII 43 Register S2 sets the ASCII value of the escape characters, used to switch the modem from Data Mode to Command Mode without losing the connection to the remote modem. Values greater than 127 disable the escape feature, preventing a return to the Command Mode. If the modem will be used to automatically answer incoming calls, either disable the escape characters of set them to a value other than that used by the originating modem. To return to Command Mode with the escape characters disabled, the remote modem must hang up or an ON-to-OFF transition of the DTR interface signal must occur with the &D1, &D2, or &D3 command in effect. S3 Carriage return character. Range Default 0-127 ASCII 13 Register S3 sets the ASCII value of the carriage return (end-of-line) character. This is the character used to end the command line (and have the modem execute the line) and also the character that appears after the modem sends a response. S4 Line feed character. Range Default 0-127 ASCII 10 Register S4 sets the ASCII value of the line feed character. The modem sends the line feed character after a carriage return only when word responds are sent (v1command in effect). If a line feed characters is not wanted,change the register value to a null character ( the line feed character cannot be totally disabled). S5 Backspace character. Range Default 0-32, 127 ASCII 8 Register S5 sets the ASCII value of the backspace character. This character is both the character created by pressing the Backspace key and the character echoed to move the cursor to the left. To change the register value, assign an ASCII value between 0 and 32, or greater than 127. Do not use values between 33 and 126 since they correspond to printable ASCII characters. S6 Wait for dial tone. Range Default 2-255 seconds 2 When the modem executes a Dial command line with the X0, X1, or X3 response set in effect, Register S6 tells the modem how long to wait after going off hook before it dials the first digit in the Dial command line. This feature is convenient when it takes linger than two seconds to obtain a dial tone. If the modem does not detect a dial tone when the tome in Register S6 elapses, you will receive the NO DIALTONE (or 6) response. S7 Wait time for carrier. Range Default 1-60 seconds 40 Register S7 tells the modem how many seconds to wait for a remote modem's carrier signal before hanging up. the register value can be increased if the modem does not detect a carrier within the specified time. If the modem detects a remote carrier signal within the specified time, it sends a CONNECT response and enters Data Mode. If it does not detect a remote carrier signal within the specified time, it sends the NO CARRIER (or 3) response, hangs up and returns to the Command Mode. S8 Pause time for comma. Range Default 0-255 seconds 2 Register S8 tells the modem how many seconds to pause for each comma (,) it encounters in a Dial command line. The comma is used when dialing through a PBX or other special telephone service to wait for an outside telephone line. An alternative to changing this register value is to include more than one comma in your command line. S9 Carrier Detect response time. Range Default 1-255 06 Register S9 tells the modem how 1/10 seconds long the remote modem's carrier signal must be present so the modem does not mistake the signal for a busy signal, ring, or voice. The factory setting requires the modem to listen to the carrier signal for at least 0.6 seconds before recognizing it. Increasing the time in this register reduces the chances that the modem will mistake noise such as a busy signal or voice for a carrier signal. For example, entering a value 15 means that the remote modem's carrier signal must be present for 1.5 seconds for the modem to recognize it. S10 Carrier loss time. Range Default 1-255 14 Register S10 sets the time 1/10 seconds between the loss of a remote modem's carrier signal and when the modem disconnects. This allows the remote modem's carrier signal to momentarily disappear from the telephone line without the modem disconnecting. the factory setting can be changed to a higher value when a noisy telephone line that might interfere with the remote modem's carrier signal. To have the modem ignore the Data Carrier Detect status and act as if the remote modem' s carrier signal is always present, set the value to 255. Assigning a value smaller than the value in Register S9 causes the modem to disconnect when it detects a momentary carrier less, because Register S10 expires before the carrier response time expires. S-Register Description S11 Range Default 50-255 ms 75 Register S11 controls the speed of the Touch-Tone (DTMF) dialing. Increasing the register value to 255 slows the dialing rate to 1.9 digits per second. Do not select a value less than 50 milliseconds. (Register S11 has no effect on pulse dialing, which is fixed at 10 pulses per second.) S12 Return to data mode timer. Range Default 0-255 40 Register S12 controls the time 1/50 seconds delay before typing the escape characters. Register S12 controls the time before returning to data mode after receiving escape characters unless "AT" command is received. S14 Functions Range Default Bit Mapped 170 Register S14 is a bit-mapped register and provides the following functions (equivalent commands are shown in parentheses): Bit 0&2 Bit0 Bit2 AT Command 0 0 Q0 0 1 Q1 1 0 Q2 Bit 1 Echo commands to DTE 0 Do not echo commands (E0) 1 Echo commands (E1) Bit 3 Word or number responses 0 Send number responses (V0) 1 Send word responses (V1) Bit 4 0 Accept commands 1 Ignore commands Bit 5 Dialing method 0 Touch-Tone (T) 1 Pulse (P) Bit 6 Reserved c Bit 7 Answer/originate operation 0 Answer (A and R) 1 Originate (D) S23 Test functions Range Default Bit Mapped 007 Register S23 is a bit-mapped register and provides the following test functions (equivalent commands are shown in parentheses): Bit 0 Response to remote modem request for Remote Digital Loopback Test 0 Ignore request (&T5) 1 Grant request (&T4) Bits1, 2, 3 DTE speed 3 2 1 0 0 0 0 0 1 300 bit/s 0 1 0 1200 bit/s 0 1 1 2400 bit/s 1 0 0 4800 bit/s 1 0 1 9600 bit/s 1 1 0 19.200 bit/s 1 1 1 38,400 bit/s Bits 4,5 Parity setting 5 4 0 0 Even parity 0 1 Space parity 1 0 Odd parity 1 1 mark parity Bits 6,7 Guard tones 7 6 0 0 Guard tones disabled (&G0) 0 1 550 Hz guard tone (&G1) 1 0 1800 Hz guard tone(&G2) 1 1 Reserved S25 DTR Delay. Range Default 0-255 seconds 5 If the &M1 command is in effect, Register S25 specifies the number of seconds that the modem waits after a connection has been made before examining the DTR lead. This delay allows a asynchronous terminal to be detached from the modem and a synchronous terminal connection while remaining in the Data Mode. After this delay S25 reverts to hundredths of seconds. S26 RTS/CTS Delay Range Default 0-255 hundreds 001 Sync Mode only. Register S2 of seconds specifies the time in hundreds of second increments, of the delay between RTS and the CTS response. S27 Test Function Bit mapped 49H Register S27 is a bit-mapped register and provides the following test functions (equivalent commands are shown in parentheses): Bit 0,1,3 Communication operation 3 1 0 0 0 0 Asynchronous operation (&M0,&Q0) 0 0 1 Synchronous operation after dialing (&M1, &Q1) 0 1 0 Synchronous terminal support (&M2, &Q2) 0 1 1 Manually originate synchronous call (&M3, &Q3) 1 0 0 Not valid 1 0 1 Asynchronous error control (&Q5) 1 1 0 Aysnchronous buffered mode (&Q6) 1 1 1 not valid Bit 2 0 Dial up line (&L0) 1 Leased line (&L1) Bit 3 Reserved Bit 4,5 Synchronous timing selection 5 4 0 0 Modem provides synchronous transmit clock on EIA pin 15 (&X0) 0 1 Modem accepts external synchronous clock (&X1) 1 0 receive clock (slave timing) (&X2) Bit 6 & 7 Bit 6 Bit7 AT Command 0 0 B0 1 0 B1 0 1 B2 1 1 B3 S30 Automatic Timeout. Range Default Register S30 specifies the number 0-255 0 of seconds the modem waits without activity, before disconnecting. Timing is in 10 second increments. S36 Negotiation Faltback Range Default 0-7 7 When the initial attempt to connect in error-control mode fails, S36 specifies what should occur next. 0 Hang up 1 Attempt a direct asynchronous connection (&Q0) 2 3 Attempt an asynchronous connection using automatic speed buffering (&q6). 4 Attempt a CCITT V.42 Alternative POrotocol connection (MNP 2-4); if negotiation fails, hang up. 5 Attempt a CCITT V.42 Alternative Protocol connection (MNP ); if negotiation fails, attempt a direct asynchronous connection. 6 7 Attempt a CCITT V.42 Alternative Protocol connection (MNP compatible); if negotiation fails, attempt an asynchronous connection using automatic speed buffering. Note: The selected fallback option can be initiated immediately with S48. For example, a connection attempt using the MNP can be forced by setting S48=128 and S36=5 or 7. S37 Maximum DCE Line Speed S37 selects the speed (for all modes except CCITT V.24bis) at which the modem attempts to connect with a remote modem; the speed selected will be the highest DCE speed supported by both modems (see S93 for CCITT V.25bis modes). 0 Speed of last AT command issued 1 75 bps 2 110 bps 3 300 bps 5 1200 bps 6 2400 bps 7 4800 bps 8 7200 bps 9 9600 bps 10 12000 bps 11 14400 bps S38 Delay Before Forced Hangup Range Default 0-255 20 S38 specifies the number of seconds the modem waits when in error-control mode (&Q5) before disconnecting after receiving the command to hang up or an on-to- off transition of DTR. The range for this register is 0-255 seconds; the default to 20 seconds. If the register is set to 0, the modem does not wait for data in the buffers to clear (gives NO CARRIER response). If the register is set to a value between 0 and 254, the modem will wait the number of seconds, or until all data has been transferred, before hanging up. (If data clears gives of response, if not gives NO CARRIER response). If the register is set to 255, the modem will not hang up until all data is transferred. S39 ATN Command Bit Map Bit 5 Bit 4 Bit 3 AT Command 0 0 0 N0 0 0 1 N1 0 1 0 N2 0 1 1 N3 1 0 0 N4 1 0 1 N5 S46 Compression Error Control protocol Selection Range Default 136,138 138 Register S46 enables d 13 No compression 138 Compression 48 Feature Negotiation Action Range Default 0, 7, 128 7 Register S48 defines whether feature negotiation is to be performed by the modem. The feature negotiation process allows the modem at ascertain the remote system's capabilities. If these capabilities are already known and negotiation is not necessary, this feature can be bypassed. 0 Negotiation disabled. Modem assumes the remote modem is configured properly to make a connection, bypasses the detection and negotiation phases, and proceeds with the protocol selected by Register S46. 3 Reserved 7 Negotiation enabled. 128 Negotiation disabled. Forces immediate fallback as specified in Register S36. Can be used to force the V.42 alternative protocol (compatible with MNP), bypassing the detection and negotiation phases. S49 Buffer Lower Limit Range Default 0-255 10 S49 specifies the minimum size of the buffer used in error-control or automatic speed buffering mode. The range is 1-255 bytes; the default setting is 10. S50 Buffer Upper Limit Range Default 0-255 200 S50 specifies the maximum size of the buffer used in error-control of automatic speed buffering mode. The range is 2-255 bytes; the default setting is 200. S63 Private Circuit Carrier Level Range Default 0-15 0 S63 specifies the carrier power level in dBm for leased line operation. This register specifies a carrier level value that is not to be exceeded. The range of this register is 0-15 (0 to - 15 dBm). The default setting is 0. S82 Beak Signaling Technique Range Default 3, 7, 128 128 S82 selects a method of break signal handling for CCITT V.42 communications: in sequence, expedited, and destructive. Break signals provide a way to get the attention of the remote host. The break type used depends on the application. 3 Expedited signaling used regardless of sequence in transmitted and received data; data integrity maintained. 7 Destructive signaling used regardless of sequence of transmitted and received data; data in process at time is destroyed. 128 In sequence signaling used as data is transmitted and received; data integrity maintained ahead of and after break. S86 Connection Failure Cause Code Range Default 0, 4-15 None S86 helps determine the cause of a connection failure. When the modem issues a NO CARRIER result code, a value is written to this S-register. To read this register following the connection failure, issue ATS86? . The modem will report one of the values below. 0 Normal hang up; no error occurred. 4 Physical carrier loss. 5 Feature negotiation failed to detect presence of another error-control modem at the other end. 6 Other error-control modem did not respond to feature negotiation message sent by this modem. 7 Other modem is sychronous- only; this modem is asynchronous-only. 8 Modems could not find a common framing technique. 9 Modems could not find a protocol in common. 10 Incorrect feature negotiation message sent by other modem. 11 Synchronous information (data of flags) not received from other modem. Modem waited 30 seconds before hanging up. 12 Normal disconnect initiated by other modem. 13 Other modem did not respond after many transmissions of the same message. modem made 10 attempts then hung up. 14 Protocol violation occurred. 15 Compression failure. Note: Multiple occurences may contribute to a NO CARRIER message; S86 records the first event that occurred.