Z02215 Datasheet, PDF (46/74 Pages) Zilog, Inc. – Single Chip Modem with Integrated Controller, Data Pump, and Analog Front End

Z02215
Single Chip Modem with Integrated Controller, Data Pump, and AFE
40
Table 7. Modem S-Registers (Continued)
Register Range
S25
0–255
Default
5
Units
seconds
or 1/100
second
Description
DTR detection. During synchronous operation with the &Q1
command in effect, S-register S25 is the number of seconds
after a telephone line connection is made before the modem
examines DTR. This action allows sufficient time to disconnect
the modem from an asynchronous terminal and attach it to a
synchronous terminal.
S26
Reserved
S27
Reserved
S28
0–255 0
S29
0–255 25
S37
0–6
0
In the ON-LINE or COMMAND state during any mode of
operation, DTR changes from S25-1 to S25 hundredths of a
second are ignored..
Reserved Reserved
Reserved Reserved
minutes
Terminal inactivity time-out. Hangs up the modem after the
number of minutes specified in S28 if no characters are
received from the modem’s terminal.
1/50th
second
Hook flash on-hook time. The amount of time in 20
millisecond units the modem leaves the telephone on-hook
while performing a hook-flash according to the ! dial string
modifier.
code
Sets the highest line rate. This register determines the
highest telephone line data rate the modem uses when
connecting with a remote modem. If S37 is set to a data rate
higher than the modem supports it attempts to connect at its
highest data rate.
The Communication Standard Options command (B) controls
which modulation standards are allowed for telephone line
data rates that feature more than one choice.
S37 refers to the telephone line data rate. The modems may
communicate with their terminals at different data rates.
In case of conflict between the B option and S37, S37 takes
precedence. Configure both modems identically to prevent
communication failures caused by incompatible telephone line
modulation standards.
See “Setting the Highest Line Rate” on page 21 for different
Communication Standards.
PS001907-0904
Modem S-Registers