V.8 Cm/Jm Signal - Xerox WorkCentre Pro 423 Service Manual

2.3.3.2 V.8 CM/JM signal

Table 1 shows the FIF configuration of the CM and JM signals used in V.8. For the details of
each bit, see below.
The V.8 standard prescribes a procedure for a modem of multiple capabilities to select
optimum mode automatically according to the line status.
The preamble and items under it are called information categories. Bits 0 to 4
are tags indicating categories and their contents are fixed. (Table 2)
* The octets of the Protocol and GSTN Access categories may not exist.
preamble
Call function
Modu. mode oct1
Modu. mode oct2
b7 b6 b5 b4 b3 b2 b1 b0
Modu. mode oct3
X
Protocol *
X
GSTN access *
X
Terminal info.
X
Table 1: CM/JM FIF
Table 2: information category
configuration
WorkCentre Pro 423/428
X X 0 0 0 0 1
Call function
X X 0 0 1 0 1 Modulation mode
X X 0 1 0 1 0
Protocol
X X 0 1 1 0 1 GSTN(General public line) access
b7 b6 b5 b4 b3 b2 b1 b0
1 1 1
preamble
X X X
Call function
X
Modu.mode
X
0
X
Modu.mode
X
0
X
Modu. Mode
RFW
X
0
X X X
Protocol
0
GSTN access
X
X
0 1 1
Terminal info.
03/02
2-107
&0-0
0 0 0 0 0
synchronous signal
100: Transmission from calling terminal 101: Reception by calling terminal
110: Data transmission and reception
111: Display by extended octet
Call function category tag
0 0 0 0 1
:V.34 half dup(28.8K bps)
1:V.34 full duplex
Reserved (Set 0)
Modulation Mode category tag
0 0 1 0 1
1:V.27ter(4800bps)
1:V.29(9600bps)
1 0
Extended octet
1:V.17(14.4K bps)
X
X
1:V.22
X
1:V.32
1:V.21(300bps)
1:V.23 half duplex
1 0 Extended octet
X
1:V.23 full duplex
X
1:V.26bis
X
1:V.26ter
001:V.24LAPM protocol
111:
Protocol displayed by extended octet

0 1 0 0 Protocol category tag
Reserved (Set 0)
1: Cellular connection on termination side
1: Cellular connection on origination side
0 1 1 0 1 GSTN access category tag
1 1 1 1 0
End of data 7Eh
Level 2 Troubleshooting
CHAPTER 2 TROUBLESHOOTING
(K
- -
Priority
2
If the priority is 1 for
two or more modulation
1
modes, the mode having
the smallest item
number in the square at
right is used.
7
...V/34 full duplex" has
6
the top priority.
5
4
The priority is 1 for the
modes whose
3
explanations are in
12
dotted line squares
11
because they are used
for fax.
10
9
8