peb2255 Infineon Technologies Corporation, peb2255 Datasheet - Page 99

• Manufacturer Part Number: peb2255
• Description: E1/t1/j1 Framer And Line Interface Component For Long And Short Haul Applications
• Manufacturer: Infineon Technologies Corporation

4.6.4
The local loopback mode, selected by LIM0.LL = 1, disconnects the receive lines RL1/2
or RDIP/RDIN from the receiver. Instead of the signals coming from the line the data
provided by system interface are routed through the analog receiver back to the system
interface. However, the bit stream is transmitted undisturbedly on the line. However an
AIS to the distant end can be enabled by setting FMR1.XAIS without influencing the data
looped back to the system interface.
Note that enabling the local loop usually invokes an out of frame error until the receiver
can resynchronize with the new framing. The serial codes for transmitter and receiver
have to be identical.
In digital interface NRZ mode, a clock must be provided on pin RCLKI (=RL2) to enable
switching into local loop mode.
Figure 29
Data Sheet
RL1
RL2
XL1
XL2
Local Loop
Local Loop (E1)
MUX
Clock +
Data
Recovery
AIS-GEN
RCLK
99
Rec.
Framer
Trans.
Framer
Functional Description E1
Elast.
Store
Elast.
Store
FALC-LH V1.3
ITS09749
RDO
XDI
PEB 2255
2000-07