Appendices
Sn - S register read / write
Introduction
Parameters
The modem selects an S register, performs a read or write operation on an S register or reports the value of an S register.
The parameters are:
Code n n = v n?
Description
Sets the S register as the default register.
Attributes the value v to the S register n.
Indicates the value of the register S n. The n parameter can be omitted, in which case it is the value of S0 which is read. S can be omitted, in which case it is the value of the last consulted S register (default register) which is read.
Examples
Result codes z z z z
ATS7 sets S7 as the default register.
ATS38 sets S38 as the default register.
AT=40 gives the default register the value of 40.
ATS=20 gives the value 20 to S0.
If the number n is outside the range of available S registers, the modem sends back an ERROR message. The value 'v' is rollover 256. If the result is outside the permitted range for a given S register, the values are still stored but from a functional point of view, it is the upper and lower limits which are used.
The input and output values are always in decimal format. Note that some S registers are read-only. In these cases, a write operation to an S register appears to be accepted but the value is in fact not written.
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