PEB24901HV1.2 Lantiq, PEB24901HV1.2 Datasheet - Page 33

• Manufacturer Part Number: PEB24901HV1.2
• Manufacturer: Lantiq

Specifications of PEB24901HV1.2

• Lead Free Status / Rohs Status: Supplier Unconfirmed

Semiconductor Group
BOUT and BIN. The input signal from the hybrid is ignored in this mode. These loops
also are referred to as "analog loops".
The analog loop mode is controlled via the IOM-2 C/I-channel. In an analog loop, the
transmit path is set to LT mode and the receive path is set to the NT mode.
3.3.1.2
The loop 2 can be closed in the NT by command from the LT side. With an internal
switch, the user data on DOUT (B + B + D) is directly fed back into DIN.
3.3.1.3
These remote loops are controlled by the exchange via C/I-channel of the Quad IEC
DFE-T . The command for closing loop 4 or loop 2 is transmitted from the exchange on
the Uk0 interface in the 1 kBaud M-channel (position 85 downstream in the Uk0 frame
from LT to NT/NT-Repeater).
To command the IEC LT-repeater to close loop 4, the NT-repeater has to find alternating
plus and zero polarity within 8 subsequent frames in the M-channel (+ 0 + 0 + 0 + 0 ...).
To command the SBC in the NT to close loop 2, the IEC in the NT has to find continuous
plus polarity within 8 subsequent frames in the M-channel (+ + + + + + + + ...). The same
code has to be found by the IEC NT-PBX or NT-TE to close loop 2 itself.
To open closed loops, the NT has to find continuous zero polarity within 8 subsequent
frames in the M-channel (0 0 0 0 0 0 0 0 ...) or at deactivation. During normal
transmission without loops, the M symbol is set to zero (or minus see section 3.4).
The NT-RP, when detecting positive M symbols, does not close loop 2, but hands them
over to a PEB 20901/20902 LT-RP via it’s IOM-1 interface with a low in the E bit of 8
subsequent IOM frames. Negative or zero M symbols cause 8 high E bits.
3.3.2 Monitoring of Code Violations
The NT transmitts a postive M symbol upstream if any code error has been detected
within a frame (position 25 upstream in the Uk0 frame from NT to LT).
The Quad IEC DFE-T contains an error counter for each channel which counts Uk0
frames with at least one detected code violation. Additionally, the frames with a received
positive M symbol are counted. The error counter can be read and simultaneously reset
from a certain state of activation via the IOM-2 interface. The counter is always stopped
after reaching 255 which is the maximum value passed to the MONITOR-channel.
The counter is automatically reset during deactivation of the Uk0 line. It is enabled again
to count code violations from the moment the RDS code is written into the IOM-2 C/I-
channel, indicating that the line is sychronized.
Each counted frame with a detected code violation leads to 10 to 20 binary bit errors on
average. So a bit error rate of 10
Switching Loop 2 in the NT
Remote Control of Loop 4 and Loop 2 by the Quad IEC DFE-T
–7
in both directions leads to about 2 detected frame
32
PEB 24901
02.95