Status Registers
10-2
V.3600
Figure 10-1 shows how the inputs to an S-register (
S22
in this example)
are used to select a particular option. Bits 3 and 2 of
S22
control
speaker options. Some communication software packages may use the
AT command set. For example purposes, bit values are arbitrary.
Bit values for S-registers must not be confused with the total register
value. Bit values are counted separately for each option group, called bit
mapping, while the register value is the cumulative decimal or
hexadecimal total. The decimal value counts all eight bits as a single
group. Hexadecimal values split the bits into two groups of four each.
Writing to an S-register changes the total value. Figure 10-2 shows the
difference between decimal calculation and hexadecimal calculation.
Figure 10-1. Changing S-Register Values
