peb2035 ETC-unknow, peb2035 Datasheet - Page 29

• Manufacturer Part Number: peb2035
• Description: Communications Advanced Cmos Frame Aligner
• Manufacturer: ETC-unknow

Transmitter
The serial bit stream is then processed by the transmitter which has the following functions:
In PCM 24 mode, the transmitter of the ACFA can be synchronized externally for multiframe begin
(port XCHPY, bit ACR.EXMF). This feature is required if the bit-robbed signals are routed through
the switching network and are inserted in transmit direction via the system interface.
Transmit Link Interface
Similar to the receive link interface two different data types with selectable output sense are
supported:
Clocking off data is done with the positive transitions of the transmit route clock: XRCLK (2048 kHz
or 1544 kHz). In PCM 30 mode, XRCLK is generated by the ACFA, whereas in PCM 24 mode it
must be generated by an external clock generator.
Additionally, the dual rail outputs XTOP and XTOM are provided for test applications.
Semiconductor Group
Frame/multiframe synthesis of one of the six selectable framing formats
Insertion of service and data link information
Remote alarm generation
CRC generation and insertion of CRC bits
Note: As addition in PCM 24 mode, all CRC bits of one outgoing extended multiframe are
inverted in case a CRC error is flagged for the previous received multiframe (function is enabled
via bit GCR.CRCI).
Dual rail data (PCM[+], PCM[–]) at ports XDOP, XDOM with 50 % or 100 % duty cycle (bit
EMOD.XFB) transmitted to a line interface unit, e.g. PEB 2235, Siemens ISDN Primary Access
Transceiver, IPAT. Single rail data is converted into a dual rail bit stream. In PCM 30 mode, the
HDB3 line code is employed. In PCM 24 mode, selection between B8ZS or simple AMI coding
with zero code suppression (B7 stuffing) is provided. B7 stuffing can be disabled on a per
channel basis (clear channel capability).
Unipolar data at port XOID (PCM 30) or at port XDOP (PCM 24) with 100 % duty cycle
transmitted to a fibre optical interface.
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PEB 2035