Specifications

TechMemo 01-0011B August 26, 2004
21 of 24
S registers
The S registers used in this section only apply to US Robotics 56K V.90 and V.92 Faxmodems.
Register Default value Function
S0 0
Sets the number of rings on which to answer in auto answer mode. When S0 = 0, auto answer is disabled
(also controlled by DIP switch #5).
S1 0 Counts and stores the number of rings from an incoming call. S0 must be greater than 0.
S2
43
(“+” character)
Stores the ASCII decimal code for the escape code character. A value of 128 to 255 disables the escape
code.
S3 13 Stores ASCII decimal value for the carriage return character. Valid range is 0 through 127.
S4 10 Stores ASCII decimal value for the line feed character. Valid range is 0 through 127.
S5 8
Stores the ASCII decimal code for the backspace character. A value of 128 to 255 disables the backspace
delete function.
S6 2
Sets number of seconds a modem waits before dialing. If Xn is set to X2 or X4, then this is the timeout
length if there is no dial tone.
S7 60
Sets the number of seconds that the modem waits for a carrier signal. For international connections, this
number should be increased.
S8 2 Sets duration, in seconds, for pause (,) option in the dial command. Valid range is 0 through 32.
S9 6
Sets required duration, in tenths of a second, of remote modem’s carrier signal before your modem
recognizes this signal.
S10 7
Sets duration, in tenths of a second, that modem waits to hang up after loss of carrier. This guard time
allows your modem to distinguish a line disturbance from a true disconnect (hang up) by the remote
modem.
S11 55 Sets duration and spacing, in milliseconds, for tone dialing.
S12 50 Sets duration, in fiftieths of a second, of guard time for escape code sequence (+++).
S13 0
Bit-mapped register (see “Settings for S13” on page 22). Select the bit(s) you want on and set S13 to the
total of the values in the Value column. For example, ATS13 = 17 enables bit 0 (value is 1) and bit 4 (value
is 16).
S14 0 Reserved.
S15 0
Bit-mapped register setup. To set the register, see instructions for S13. See “Settings for S15” on
page 22.
S16 0 Reserved.
S17 0 Reserved.
S18 0
Test timer for &T loopback testing. Sets the time in seconds of testing before the modem automatically
times out and terminates the test. When set to 0, the timer is disabled. Valid range is 1-255.
S19 0
Sets duration, in minutes, for inactivity timer. This timer activates when there is no data activity on the
phone line. At time-out the modem hangs up. S19 = 0 disables the timer.
S20 0 Reserved.
S21 10
Sets length, in 10-millisecond units, of breaks sent from the modem to the computer. This applies to
MNP or V.42 mode only.
S22 17 Stores ASCII decimal code for the XON character.
S23 19 Stores ASCII decimal code for the XOFF character.
S24 0 Reserved.
S25 5
Sets duration, in hundredths of a second, of a true DTR drop. Prevents modem from interpreting random
glitches as DTR loss. (Most users will use the default. This register is useful for compatibility with older
systems and operating software.)
S26 0 Reserved.
S27 0 Bit-mapped register setup. See “Settings for S27” on page 23.