PEF24901HV22XP Lantiq, PEF24901HV22XP Datasheet - Page 76

• Manufacturer Part Number: PEF24901HV22XP
• Manufacturer: Lantiq

Specifications of PEF24901HV22XP

• Control Interface: HDLC
• Lead Free Status / Rohs Status: Compliant

4.4.1
Four different loopbacks are defined for maintenance purposes and in order to facilitate
the location of defect systems. The position of each loopback is illustrated in
Remote control by the exchange is featured. When a test loop is closed all channels (B1
+ B2 + D) are looped back and data from the other end of the line is ignored. There are
no separate loops for single channels.
•
Figure 26
All test loops are transparent loops. The line signal is still transmitted although the analog
loop is closed. Nevertheless the NT receives this signal and synchronizes on it. The NT
can not distinguish between line signals sent from the LT during loop 1 or loop 4 and
signals sent during normal operation. Loopback no.1 is closed by the DFE-T V2.2 itself,
whereas loopback no 4 and no.2 are remote controlled by C/I code ’AR4’ and ’AR2’ and
are closed in the repeater or in the NT, respectively. Loopback no.3 is not supported
since the DFE-T V2.2 operates only in LT mode.
4.4.1.1
The analog loop no.1 is closed in the DFE-T V2.2 as close to the U-interface as possible.
The signal from the line driver is fed back directly to the input. It is like a short-circuit
between the pins AOUT and AIN as well as between BOUT and BIN. The input signal
Data Sheet
S-BUS
Layer-1 Controller
Layer-1 Controller
S-Transceiver
Test Loopbacks
Analog Loopback (No.1)
Loop 2
Test Loopbacks
PBX or TE
IOM
IOM
IOM
NT
®
®
®
-2
-2
-2
U-Transceiver
U-Transceiver
U-Transceiver
Loop 2
Loop 2
Loop 2
Loop 3
U
U-Transceiver
Loop 4
77
Repeater
IOM
(optional)
®
-2
U-Transceiver
Operational Description
U
U-Transceiver
Exchange
Loop 1
loop_4b3t
PEF 24901
IOM
Figure
2002-09-30
®
-2
DFE-T
26.