peb2255 Infineon Technologies Corporation, peb2255 Datasheet - Page 133

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

PEB 2255
FALC-LH V1.3
Functional Description T1/J1
5.3.3
Transmitter (T1/J1)
The serial bit stream is then processed by the transmitter which has the following
functions:
• Frame/multiframe synthesis of one of the four selectable framing formats
• Insertion of service and data link information
• AIS generation (Blue Alarm)
• Remote alarm (yellow alarm) generation
• CRC generation and insertion of CRC bits
• CRC bits inversion in case of a previously received CRC error or in case of activating
per control bit
• Generation of Loop Up/Down code
• IDLE code generation per DS0
The frame/multiframe boundaries of the transmitter may be externally synchronized by
using the SYPX/XMFS pin. Any change of the transmit time slot assignment
subsequently produces a change of the framing bit positions on the line side. This
feature is required if signaling and data link bits are routed through the switching network
and are inserted in transmit direction via the system interface.
In loop-timed configuration (LIM2.ELT = 1) disconnecting the control of the transmit
system highway from the transmitter is done by setting FMR5.XTM. The transmitter is
now in a free running mode without any possibility to update the multiframe position in
case of changing the transmit time slot assignment. The FS/DL bits are generated
independently of the transmit system interface. For proper operation the transmit elastic
buffer size must be programmed to 2 frames.
The contents of selectable time slots may be overwritten by the pattern defined via
register IDLE. The selection of “idle channels” is done by programming the three-byte
registers ICB1 … ICB3.
If AMI coding with zero code suppression (B7-stuffing) is selected, “clear channels”
without B7-stuffing can be defined by programming registers CCB1 … CCB3.
Data Sheet
133
2000-07