Bit-Mapped S-Registers - 3Com 3C421600A Reference Manual

Bit-Mapped Understanding Bit-Mapped S-Registers
S-Registers
Certain S-Registers are bit-mapped. Bit-mapped registers appear in RAS
1500 documentation as the following: ATS56.1=1 and ATS68.4=0. A
bit-mapped S-Registers uses one number to describe a collection of
settings. Bit-mapping allows modem developers to pack a lot of
information in a small space.
When RAS 1500 displays the value of an S-Register, you see a decimal
value between 0 and 255. RAS 1500, however, understands the decimal
value as a collection of binary digits (bits).
Setting Bit-Mapped S-Registers
You can set bit-mapped S-Registers using either bits or decimal values.
While it may be simpler for you to set the bits individually, RAS 1500
displays the S-Register settings in decimal form.
Bits and decimal values
For bit-mapped S-Registers, eight bits are assigned. Each bit is either on
(1) or off (0). Eight bits create 256 unique combinations of 1s and 0s.
Each of the eight bits is assigned a number corresponding to its position
as in the following example:
b b b b b b b b
7 6 5 4 3 2 1 0
Each bit can be assigned a value corresponding to its number. Use the
following table to understand the relationship of bits to the decimal
value.
Table A-9 Bit-mapped S-Register Explanation
Value
S78=1
S78=2
S78=4
S78=8
S78=16
S78=32
S78=64
S78=128
Using S-Register Commands A-233
Bit Visual representation
S78.0=1 0 0 0 0 0 0 0 1
S78.1=1 0 0 0 0 0 0 1 0
S78.2=1 0 0 0 0 0 1 0 0
S78.3=1 0 0 0 0 1 0 0 0
S78.4=1 0 0 0 1 0 0 0 0
S78.5=1 0 0 1 0 0 0 0 0
S78.6=1 0 1 0 0 0 0 0 0
S78.7=1 1 0 0 0 0 0 0 0