PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 78

• Manufacturer Part Number: PEF2091
• Description: ICs for Communications(ISDN Echocancellation Circuit)
• Manufacturer: Siemens Semiconductor Group

Semiconductor Group
M 1/2:Monitor message 1. and 2. byte
R 1/2:Monitor response 1. and 2. byte
EOM:End of message: MX=’1’ and MR=’1’ in two consecutive IOM
Figure 28
Idle State
After the bits MR and MX have been held inactive (i.e. high) for two or more successive
IOM
Transmission Abortion
If no EOM is detected after the first two monitor bytes, or received bytes are not identical
in the first two received frames, transmission will be aborted through receiver by setting
the MR-bit inactive for two or more IOM
situation is illustrated in figure 29 below.
®
-2-frames, the channel is considered idle in this direction.
IOM -2 Frame
DIN
Mon.
DOUT
Mon. Data
R
Data
Handshake Protocol with a 2-Byte Monitor Message/Response
MX
MR
DIN
MX
MR
DOUT
No.
1
0
1
0
1
0
1
0
Tx 1.Byte
M
FF
Ack. 1.Byte
1
1
M
FF
2
1
M
FF
3
2
Tx
M2
FF
2.Byte
Ack.
4
FF
FF
2.Byte
®
5
-2-frames. The controller reacts with EOM. This
FF
FF
78
6
EOM
EOM
FF
FF
7
Tx
R 1
FF
8
1.Byte
FF
R 1 R 1 R 2
9
Ack.
1.Byte
10
FF
Tx 2.Byte
FF
11
Functional Description
R
FF
12
Ack. 2.Byte
2
®
-2-Frames.
FF
FF
13
Data Sheet 01.99
EOM
14
FF
FF
ITD04230
EOM
PEB 2091
PEF 2091
FF
FF
15