PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 79

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

Figure 29
Example: Standard Transmission Procedure in stand-alone mode
1. The first byte of monitor data is placed by the external controller (e.g. ICC, EPIC
2. The IEC-Q reads the data of the Monitor Channel and acknowledges by setting the
3. The second byte of monitor data is placed by the controller on DIN and the MX-bit is
4. The IEC-Q reads the new data byte in the Monitor Channel after the rising edge of MX
5. After both monitor data bytes have been transferred to the IEC-Q, the controller
6. In the frame following the transition of the MX-bit from active to inactive, the IEC-Q
7. If the IEC-Q is requested to return an answer it will commence with the response as
Semiconductor Group
the DIN line of the IEC-Q and MX is activated (low; frame No. 1).
MR-bit of DOUT active if the transmitted bytes are identical in two received frames
(frame No. 2 because the IEC-Q reads and compares data already while the MX-bit
is not activated).
set inactive for one single IOM
controller.
has been detected. In the frame immediately following the MX-transition
active-to-inactive, the MR-bit of DOUT is set inactive. The MR-transition
inactive-to-active exactly one IOM
the external controller (frame No. 4–5).
The acknowledgment by the IEC-Q will always be sent two IOM
activation of a new data byte.
transmits "End Of Message" (EOM) by setting the MX-bit inactive for two or more
IOM
sets the MR-bit inactive (as was the case in step 4). As it detects EOM, it keeps the
MR-bit inactive (frame No. 6). The transmission of the monitor command by the
controller is complete.
soon as possible. In case the "monitor time-out" function is enabled it may have to
®
-2-frames (frame No. 5–6).
Abortion of Monitor Channel Transmission
IOM -2
R
DIN
DOUT
Frame
MX
MR
MX
MR
No.
1
1
1
1
0
0
0
0
®
-2-frame. This is performed at a time convenient to the
1
®
-2-frame later is regarded as acknowledgment by
2
Abort Request from Receiver
3
79
4
EOM
5
6
7
ITD04231
Functional Description
®
-2-frames after the
Data Sheet 01.99
PEB 2091
PEF 2091
®
) on