PEB22554 SIEMENS [Siemens Semiconductor Group], PEB22554 Datasheet - Page 265

• Manufacturer Part Number: PEB22554
• Description: ICs for Communications
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Local Loop
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 will be undisturbed transmitted on the line. However
an AIS to the distant end could be enabled by setting FMR1.XAIS without influencing the
data looped back to the system interface.
Note that enabling the local loop will usually invoke an out of frame error until the receiver
can resync to the new framing. The serial code from the transmitter and receiver has to
be programmed identically.
Figure 67
Local Loop
Semiconductor Group
RL1
RL2
XL1
XL2
MUX
Clock +
Data
Recovery
AIS-GEN
RCLK
265
Rec.
Framer
Trans.
Framer
Functional Description T1 / J1
Elast.
Store
Elast.
Store
ITS09749
PEB 22554
RDO
XDI
09.98