Chapter 4. S registers


S0

Sets the number of rings on which to answer when modem is set to Auto Answer mode, [Default = 1] (also DIP switch 5)


S1

Stores the number of rings received [Default = 0].


S2

Stores the ASCII decimal code for the escape code character [Default = 43, "+" character].


S3

Stores the ASCII decimal code for the carriage return <CR> character [Default = 13].


S4

Stores the ASCII decimal code for the line feed <LF> character [Default = 10].


S5

Stores the ASCII decimal code for the backspace character <BS> [Default = 8].


S6

Stores the number of seconds that the modem will wait before executing a dial string [Default = 2].


S7

Stores the number of seconds modem will wait for a carrier signal after executing a dial string or answer before returning onhook and sending a "NO CARRIER" result code to the DTE [Default = 60].


S8

Stores the number of seconds for pause option (,) in the Dial command.


S9

Stores the number of tenths of a second that modem will receive carrier signal before recognizing a valid connection [Default = 6]. Modem ignores setting above 2400 bps due to length of handshaking sequences.


S10

Stores the number of tenths of a second that modem will wait after loss of carrier before disconnecting [Default = 7].


S11

Stores the duration and spacing, in milliseconds, of dialed touch tones [Default = 70].


S12

Stores the duration, in fiftieths of a second, for the guard time of the escape sequence [Default = 50].


S13

Options register [Default = 0]. Bit mapped options are selected/deselected by the binary representation of the following decimal values:

1
Reset modem when DTR is not asserted,
2
Reset non MNP transmit buffer from 1.5K bytes to 128 bytes.
(Previously S15.3)
4
Set backspace key to delete.
(Previously S15.5)
8
Autodial the number stored in NVRAM location 0 when DTR is asserted.
16
Autodial the number stored in NVRAM location 0 upon software reset or when modem is powered up.
32
Disable V.32bis ASL mode.
(Previously S34.1)
64
Disable Quick Retrains
(Previously S34.2)
128
Disconnect on escape code.
(Previously S14.0)

S14

Reserved


S15

ARQ Options register [Default = 0]. Bit mapped options are selected/deselected by the binary representation of the following decimal values:

1
Disable ARQ/MNP for V.22
(Previously S51.0)
2
Disable ARQ/MNP for V.22bis
(Previously S51.1)
4
Disable ARQ/MNP for V.32/V.32bis/V.32terbo
(Previously S51.2)
8
Disable MNP handshake.
(Previously S27.4)
16
Disable MNP level 4.
32
Disable MNP level 3.
(Previously S13.6)
64
MNP incompatibility.
128
Disable V.42 operation.
(Previously S27.5)

Notes for S15=64 setting:


S16

Test mode [Default = 0]. Settings are as follows:

1
Reserved.
2
Dial test when a touch tone digit is entered from the DTE in a dial string, the tone continues until a carriage return character from the DTE aborts it for testing purposes.
4
Test pattern generation A test pattern is generated by the Modem and sent out over the phone link. A key press abort will terminate this function.
8-128
Reserved.

S17

Reserved


S18

Stores the time in seconds for the diagnostics test mode &T. A value of 0 disables timer, a value of 1 255 are acceptable [Default = 0].


S19

Stores the duration, in minutes, for inactivity timer. If modem senses no data transmission for a time exceeding the nonzero value in this register, it will disconnect the call. A value of 0 disables the function [Default = 0]. Any value other than 0 enables it.


S20

Reserved.


S21

Stores, in 10 millisecond increments, the lengths of break characters sent from modem to DTE [Default = 10]. For use in MNP or V.42 mode only.


S22

Stores ASCII decimal code for the XON character [Default = 17].


S23

Stores ASCII decimal code for the XOFF character [Default = 19].


S24

Reserved


S25

Sets DTR recognition time in hundredths of a second. [Default = 20].


S26

Reserved


S27

Connection bit mapped operations. Stores various modulation and error correction control flags. [Default = 0].

1
V.21/ Bell 103 mode select [Default = Bell 103].
2
Enable unencoded modulation in V.32 mode.
4
Disable V.32 modulation.
8
Disable 2100 Hz answer tone.
16
Enable V.23 fallback mode
(Previously S34.3 )
32
Used to disable V.32bis mode
(Previously S34.0 )
64
Disable V.42 Selective Reject
128
Software compatibility mode. All connect messages above or equal to 9600 bps are expressed as "CONNECT 9600".

S28

V.32 handshaking time. (Allowable times are 025.5 seconds)

0
Eliminates the V.32 answer tones for a faster connection.
8
Default time in tenths of seconds.
255
disable all connections except V.32 9600 bps.

S29

V.21 answer mode fallback timer. Time in 1/10 second intervals. [Default = 20].


S30

Voice View deadman timer function [Default = 0]


S31

TAD Audio level adjust [Default = 128].


S32

Connection bit mapped operations. Stores various modulation and call control flags. [Default = 0].

1
V.8 Call Indicate enable [Default = Off].
2
Enable V.8 mode.
4
Disable V.FC modulation.
8
Disable V.34 modulation.
16
Disable V.34+ modulation.
32
Disable x2 modulation.
64
Reserved.
128
Reserved.

S33

V.34 & V.34+ Connection setup bit mapped control flags. [Default = 0].

1
Disable 2400 Symbol rate.
2
Disable 2743 Symbol rate.
4
Disable 2800 Symbol rate..
8
Disable 3000 Symbol rate..
16
Disable 3200 Symbol rate.
32
Disable 3429 Symbol rate.
64
Reserved
128
Disable Shaping.

S34

V.34 & V.34+ Connection setup bit mapped control flags. [Default = 0].

1
Disable 8S-2D trellis encoding.
2
Disable 16S-4D trellis encoding.
4
Disable 32S-2D trellis encoding.
8
Disable 64S-4D trellis encoding.
16
Disable Non linear coding.
32
Disable TX level deviation
64
Disable Preemphasis.
128
Disable Precoding.

S35

x2 Connection setup bit mapped control flags. [Default = 0].

1, 2, 4
These bits combine to limit the x2 back channel maximum speed.
1
2
4
Decimal
Function
0
0
0
0
No back channel limit
1
0
0
1
28800 max
0
1
0
2
26400 max
1
1
0
3
24000 max
0
0
1
4
21600 max
1
0
1
5
19200 max
0
1
1
6
16800 max
1
1
1
7
14400 max
8
Enable x2 server operation. (Default = 0)
16
Enable x2 A law operation. (Default = 0)
32
Disable automatic A/m law detection. (Default = 0)
64
Disable reduced power. (Default = 0)
128
Reserved.

S36 to S37

Reserved


S38

Sets an optional delay, in seconds, before a forced hangup and clearing of the Transmit buffer when DTR drops during an ARQ call. This allows time for a remote modem to acknowledge receipt of all transmit data before it is disconnected. Default is 0: the modem immediately hangs up when DTR drops.


S39

Reserved for International Usage.


S40

Reserved for International Usage.


S41

Bit Mapped [Default = 0].

1
Distinctive Ring Enable
Bits 1 2: Reserved.
8
Message Waiting (Voice products only)
Bits 4-7
Reserved

S42

Bit mapped

Bit 0 2 GPI definition (Mac Voice Only)
0 = Not Active
1 = CD signal
2 = RI Signal
3 = DSR Signal
4 = ARQ Signal
5 7 Undefined