Specifications
88 MultiModemISI Hybrid Series, ISIHI-2S/2U
Chapter 4—MODEM AT Commands, S-Registers, Result Codes
Reading and Assigning S-Register Values
Use the S command to assign a value to an S-register and to read an its current value. To
read an S-register value, in terminal mode, type S, the S-register number, and a question
mark (?), and press ENTER. For example, to display the value of register S7, type ATS7?
and press ENTER. The value appears as a three-digit decimal number (e.g., 045).
To assign a new value to an S-register, type S, the S-register number, an equals sign (=),
and a decimal number. Convert all ASCII characters to their decimal equivalents before
entering. Valid S-register decimal values are shown for each register in the previous
section. To make the change permanent, use the &W0 command.
Examples of Assigning Values
1. You want to have longer pauses caused by the comma in a dial command: five
seconds instead of two. Type ATS8=5 to assign 5 as the value for register S8. The
modem now pauses five seconds for every comma in a dial command.
2. You want to configure your modem to answer incoming calls after the fourth ring
instead of after the first ring. To configure register S0 with a value of 4, type ATS0=4
and press ENTER.
3. You are calling long distance to another country code, and it is taking a long time to
connect. The register S7 (time to wait for carrier) factory default setting of 50 seconds
is insufficient; a time-out occurs and cancels the call before a connection is made. To
change the S7 value to 75 seconds, type ATS7=75 and press ENTER . Now, after
dialing, the modem allows 25 more seconds for a carrier signal before aborting the
call. The additional 25 seconds should provide enough time for international calls.
Examples of Reading Values
1. To verify that you entered the value correctly in the preceding examples, type ATS8?
and press ENTER in the first example, ATS0? in the second example, and ATS2? in
the third example. You should receive the responses 005, 004, and 075, respectively.
2. When configuring S-registers, it is a good practice to include the verification read
command in the same command string as the configuration assignment command. In
the three preceding examples, type ATS8=5S8?, ATS0=4S3?, and ATS7=75S7?,
respectively.
AT Commands that Affect S-Registers
For maximum throughput, the ISIHI-2S/2Us default configuration is for originating a
call to another 33,600 bps modem that supports error correction, data compression, and
flow control. If the receiving modem is not compatible, the ISIHI-2S/2U can match any
ITU-T or Bell standard modem (but not proprietary protocols).
If you require a different configuration for your applicationfor example, if you want to
use an ISIHI-2S/2U modem strictly as an auto answering device or for service that does
not support error correctionyou can change the command parameters and S-register
values in active memory and save the new values with the &W command.