peb2255 Infineon Technologies Corporation, peb2255 Datasheet - Page 155

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

5.6.4
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. The bit stream is transmitted on the line undisturbedly. 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 to 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 54
Data Sheet
RL1
RL2
XL1
XL2
Local Loop
Local Loop (T1/J1)
MUX
Clock +
Data
Recovery
AIS-GEN
RCLK
155
Rec.
Framer
Trans.
Framer
Functional Description T1/J1
Elast.
Store
Elast.
Store
FALC-LH V1.3
ITS09749
RDO
XDI
PEB 2255
2000-07