Subject: S.Registers

From: [email-masked] (Matthew Pearce)
Date: 13 May 1994 19:52:54 -0700

The following information is from my Practical Peripherals PM14400FXMT 
manual.
 
[chart] signifies a chart in the manual that I haven't included.
 
... signifies more info is available.
 
If you need either of the above, post a request.
 
"Many of the S-Registers are labeled reserved.  These either contain 
parameter
bit maps for the internal use of the modem or are not in current use..."
 
S0 RING TO ANSWER ON
 
S0 sets the number of rings required before the modem picks ups the telephone
line to answer an incoming call (Auto answer).  The value can be any number
between 0 and 255.  S0=0 disables the auto-answer function.
 
S1 RING COUNT
 
S1 accumulates the number of rings sensed on the telephone line.  S1 
resets to
0 if a ring is not sensed within any eight-second interval.  When S0 
contains a
non-zero value between 1 and 255 and the count in S1 equals the value in S0,
the modem goes off-hook to answer the call.
 
S2 ESCAPE CODE CHARACTER
 
S2 hold the value of the ASCII character used as the modem escape code.  The
default is 43 - the "+" character. ... The escape code function is 
disabled if
the value of S2 is greater than 127.
 
S3 CARRIAGE RETURN CHARACTER
 
S4 LINEFEED CHARACTER
 
S5 BACKSPACE CHARACTER
 
S6 WAIT TIME BEFORE BLIND DIALING
 
Specifies the amount of time the modem waits after going off-hook before
dialing the first digit of the dial string.  S6 can be set to any value 
between
2 and 255 seconds.  The W (wait for dial tone) modifier overrides the value
contained in S6 and dials the first digit as soon as a dial tone is detected.
 
S7 WAIT FOR CARRIER AFTER DIAL
 
The value of S7 specifies the number of seconds the originating modem 
waits for
carrier from the answering modem. ...  S7 sets the period the originating 
modem
waits for dial tone, quiet, or bong (calling-card prompt tone) with the 
W, @,
and $ dial modifiers respectively.  The valid range is 1 to 255 seconds 
with a
default of 50 seconds.
 
S8 WAIT TIME FOR COMMA DIAL MODIFIER
 
Specifies the number of seconds to pause for each comma (,) encountered 
in a
dial string or command line.  The default is two seconds, but any value 
between
0 and 255 is acceptable.
 
S9 CARRIER DETECT RESPONSE TIME
 
S9 specifies the time-in 0.1 second units-that a received carrie must be
present on the line before the modem recognize it as a valid carrier and send
the Data Carrier Detect (DCD) signal.  ... The S9 default is 0.6
 
S10 LOST CARRIER TO HANG-UP DELAY
 
Specifies the time the on-line modems waits after a carrier loss before it
hangs up the telephone line.  The default is 1.4 seconds.  Setting S10 to 255
disables the hang-up function.  S10 should always be greater than S9 or the
modem will hang up in response to even a momentary loss of the carrier 
signal.
The valid range is 1 to 255 in tenths of a second (0.1 to 25.5 seconds).
 
S11 DTMF DIALING SPEED
 
Specifies the duration of the tones in Dial Tone Multi-Frequency (DTMF)
dialing.  The value can range between 50 and 255 mili-seconds.  The 
default is
95 miliseconds.  The value of s11 has no effect on pulse dialing.
 
S12 ESCAPE CODE GUARD TIME
 
Specifies the delay time required-before and after the entry of the escape
sequence-before the modem recognizes the escape sequence as valid. ... The
guard time is in units of 20 milliseconds ( 1/50th of a second). ...
 
S13-S17 RESERVED
 
Some S-Registers are reserved.  These either contain parameter bit maps 
for the
internal use of the modem of are not in current use.  Do not alter or write
directly to any of these reserved S-Registers.  This could result in 
unreliable
and unpredictable operation of your modem.
 
S18 MODEM TEST TIMER
 
Establishes the duration-in seconds in which the modem performs a diagnostic
test.  The default of zero disables the test timer and allows the test to run
indefinitely.
 
S19-24 RESERVED
 
S25 DTR DETECTION
 
In Synchronous Mode 1 (AT&Q1), S25 specifies the length of time-in full
seconds-the modem waits after a connection has been made before examining the
Data Terminal Ready (DTR) signal. ...
 
S26 RTS-TO-CTS DELAY INTERVAL
 
This register specifies the time interval to delay between and off-to-on
transition of Request to Send (RTS) and turning on Clear to Send (CTS). ...
 
S27-S29 RESERVED
 
S30 INACTIVITY TIMER
 
S30 specifies the period of data inactivity, while on-line, after which the
modem hangs up the telephone line.  The default-which disables the 
function-is
0 (zero).  The valid range is 0 to 255 in ten-second intervals.  This 
function
is applicable to all buffered modes.  It is not supported when the modem is
configured with the AT&Q0 command.
 
S31-S35 RESERVED
 
S36 PROTOCOL NEGOTIATION FALLBACK
 
S36 specifies the subsequent action for the modem to take when the initial
error-control negotiation fails.
 
[chart]
 
S37 MAXIMUM DCE SPEED
 
S37 selects the speed at which your modem attempts a connection with the 
remote
modem.  This is the data transmission speed across the telephone line from
modem to modem.  The remote modem does not support the speed specified in 
S37,
your modem will attempt to connect at the next lower speed. ...
 
[chart]
 
S38 DELAY BEFORE FORCED HANG-UP
 
S38 specifies the number of seconds before a modem in error-control mode
(AT&Q5) waits before disconnecting in response to either receiving a 
command to
hang up the line or detecting an on-to-off transition of DTR when AT&D2 
is set.
...
 
S39-S42 RESERVED
 
S43 CURRENT DCE SPEED
 
S43 is a read-only S-Register that contains a value defining the DCE 
speed of
the most current connection.  This S-Register is read by certain 
communications
programs for their internal processing.
 
[chart]
 
S44-S45 RESERVED
 
S46 DATA COMPRESSION
 
S46 is used to turn data compression ON or OFF.  Your modem does not attempt
negotiation of data compression if S46 = 0.  Your modem will negotiate 
with a
remote modem for data compression if S46 = 2.  This is the factory default.
...
 
S47 RESERVED
 
S48 V.42 FEATURE NEGOTIATION ACTION
 
If the capabilities of the remote modem are known, S48 can be used to either
tailor the negotiation to suit or bypass the negotiation phase 
completely.  The
S48=7 default enables feature negotiation.  Any invalid entry is 
interpreted by
the modem as S48=128.
[chart]
 
S49 BUFFER LOWER LIMIT
 
S49 specifies the minimum size of the buffer used in error-control or 
automatic
speed-buffering mode.  The buffer size can range from 1 to 249 bytes.
 
S50 BUFFER UPPER LIMIT
 
S50 specifies the maximum size of the buffer used in error-control or 
automatic
speed-buffering mode.  The buffer size can range from 2 to 250 bytes.  If S50
<= S49, then the factory defaults are used.
 
S51-S62 RESERVED
 
S63 PRIVATE CIRCUIT CARRIER LEVEL
 
S63 specifies the carrier power level, in decibels per minute (dbm), for 
leased
line operation.  This S-Register specifies a carrier-level value that is 
not to
be exceeded.  The permissible range is 0 to 15 (0 to -15 dBm).  The 
default is
0.
 
S64-S81 RESERVED
 
S82 BREAK HANDLING OPTIONS
 
S82 defines the method used to send a BREAK to the remote system to get the
attention of the remote modem.
 
[chart]
...
 
S83-S85 RESERVED.
 
S86 CONNECTION FAILURE CAUSE CODES
 
When the modem fails to make a connection and returns the NO CARRIER result
code, a value is written in S86 which defines to cause of the failed
connection.  S86 records the first even that causes a NO CARRIER message to
occur.
[chart]
 
S87-S94 RESERVED
 
S95 NEGOTIATION MESSAGE OPTIONS
 
S95 enables various result messages pertaining to an error-controlled
connection.  This S-Register does not alter the way the connection os
negotiated, it just enables extended messages.
[chart]
...
 
S96 RESERVED
 
S97 V.32 AUTOMODE V.22/V.22BIS PROBE TIMING
 
S97 set the duration fo the signal-in 0.1 second units-used by the modem 
in the
answer mode during a V.32 automode handshake to determine if the calling 
modem
is a V.22 or a V.22bis-type modem.
...
 
S98-S107 RESERVED
 
S108 SIGNAL QUALITY SELECTOR
 
This S-Register sets the signal quality required for the modem to 
handshake at
the highest designated V.32bis speed and for automated rate re-negotiation.
If, during carrier handshake, the modem determines that the signal 
quality is
less than that specified by S108, the modem will attempt to connect at 
the next
lower speed indicated by S109-unless ATN0 command has been selected.  I the
ATN0 command has been selected, only the speed indicated by S-Register 
S37 can
be used.
[chart]
 
S109 V.32bis CARRIER SPEED SELECTOR
 
S109 controls that speeds available for V.32bis carrier handshake.  This
permits you to disable speeds slower that the highest carrier speed or other
carrier speeds.  S37 selects the highest carrier speed.
[chart]
...
 
S110 V.32/V.32bis SELECTOR
 
The V.32 and V.32bis carrier handshake procedures are compatible.  The rate
sequence contains bit combinations that specify the procedures to be used.
 
S110 provides control of that selection for users who want to limit carrier
handshake procedure to that specified by V.32 or disable automatic rate
re-negotiation (rate changes initiated by the modem based on signal quality)
 
When S110=0, the V.32 handshake procedure is followed, rate re-negotiation
allowed by V.32bis is disabled, and the AT&Un command determines whether 
or not
trellis encoding is enabled.
 
When S110=1, the V.32bis handshake is enabled, but not automatic 
renegotiation.
The modem responds to a rate re negotiate request from the remote end.
 
When S110=2 (the factory default), V.32bis handshake and automatic rate
re-negotiation are enabled.
 
S111-255 RESERVED.

M.P.