Note: The default settings for your modem may differ from those listed here. See the supplied Installation Guide for details of any differences.

To alter the value of an S register the Sn=v command is used, where n is the number of the register and v is the value. If a value outside the range of the register is entered the modem sets the value to the nearest maximum or minimum value. No ERROR message is generated. To view the contents of a single register enter the Sn? command.

Example : ATS0=5 <Return> will cause the modem to answer after 5 rings.

The contents of the register are reset to zero when the modem answers an incoming call.

Note: This register is read only.

When the modem is being used to run a host system it may be wise to redefine the escape code character. For instance, the host system provides a remote echo facility for callers i.e. it echoes received characters back to the caller. The caller is running a modem with the AT command set. When the caller issues the escape sequence it is passed to the host system via the modem. The host system in turn echoes back the escape sequence to the caller via the modem. However, because the modem cannot distinguish between an escape sequence typed at the DTE and the echo of an escape sequence it goes into command mode. From this it can be seen that a change in the escape code character can be very useful!

Example: ATS3=10 <Return> sets the ASCII character 10 <LF> as the recognised <CR> character.

Here the original <Return> character was used to execute the command but from now on further commands must be terminated with the new value. i.e. <LF>

However, some computers use ASCII 8 (backspace) in place of 127, although this does not usually delete the character concerned; it simply backspaces the cursor so that you can over type the incorrect character.

S5 contains a value which the modem accepts (in addition to ASCII 127) to effect a delete and is, by default, set to 8. If your computer uses any other character to represent delete or backspace, simply set S5 with the appropriate ASCII code.

With dial tone detection enabled (X2 or X4) the modem dials immediately after getting the dial tone, ignoring the status of S6. Disabling dial tone detection (X0, X1 or X3) forces the modem to blind dial, i.e. the modem dials regardless of the presence or absence of a dial tone, after the period specified in S6.

In the example above the "," is used in place of the W command. This may be useful where the frequency of the secondary dial tone is such that it cannot be distinguished by the modem. In this example the modem dials 9, waits for 2 seconds (the default) then proceed to dial 01234 567890.

For error corrected connections, each time data is transferred the timer is reset. For non-error corrected connections, only transmitted data resets the timer. The timer is inoperative in synchronous mode. A sensible value in most situations is 10 minutes (i.e. a value of 60). Setting the register to 0 disables the timer.

When in voice mode S30=0 sets the deadman timer to off. No matter how long the period of inactivity lasts, the modem never hangs up the telephone line or switches to auto-baud mode.

When in voice mode S30=n where n has the range 1 to 255. This is the period of time in seconds, which if expired causes the modem to hang up the telephone line if it is off hook and no data has passed during that period. The timer is also active whenever the #BDR setting is non zero. To avoid a state where speed sense is disabled, the inactivity time-out occurs if there is no data passed on the DTE interface within the S30 period, even if the modem is on hook. The DTE software must not select a non zero setting for #BDR until it is ready to establish a telephone call or virtual connection to a speaker or microphone. When there is an inactivity time-out with #CLS=8, the modem always forces #CLS=0 and #BDR=0.

If S38 is set to a value between 0 and 254, the modem will wait that number of seconds for the remote modem to acknowledge all data in the modem buffer before disconnecting. If time expires before all the data is sent, the NO CARRIER result code will be issued to indicate that the data has been lost. If all data is transferred prior to time-out, the response to the H0 command will be OK.

If S38 is set to 255, the modem does not time-out and continues to attempt to deliver data in the buffer until the connection is lost or the data is delivered.

The table below shows the available combinations and the value to be entered in register S80.

ATS80=193 <Return>

A reset (power on or Z command) is required to effect the change made by altering the value of S80.

The options may be individually enabled in any combination. There is a decimal value corresponding to each message option available which must be entered in the register. To select more than one option at a time, add the decimal values corresponding to each option together and enter the sum total into the register.

A value over 127 disables the escape process i.e. no escape character is recognised. The default S202 value 170 disables the escape process to Remote access (whereas the default value of S2 enables escape to command mode). If 128 is subtracted from 170 (i.e. bit 7 is reset), the resulting 42 is the ASCII code for the "*" character. The "*" is commonly used for the Remote access escape character.

The Remote access escape sequence works when the modems are connected in any mode (normal, LAPM or MNP) except direct mode. The modem on which the remote commands are typed (the local modem) does not require any special code associated with the remote configuration. The remote modem (whose configuration will be modified remotely) must have remote configuration enabled. See the description of the register S80 for more information.