
DS3161/DS3162/DS3163/DS3164
10.10 DS3/E3 Framer / Formatter
10.10.1 General Description
The Receive DS3/E3 Framer receives a unipolar DS3/E3 signal, determines frame alignment and extracts the
DS3/E3 overhead in the receive direction. The Transmit DS3/E3 Formatter receives a DS3/E3 payload, generates
framing, inserts DS3/E3 overhead, and outputs a unipolar DS3/E3 signal in the transmit direction.
The Receive DS3/E3 Framer receives a DS3/E3 signal, determines the frame alignment, extracts the DS3/E3
overhead, and outputs the payload with frame and overhead
The Transmit DS3/E3 Formatter receives a DS3/E3 payload from the ATM/Packet Processor, generates a DS3/E3
frame, optionally inserts DS3/E3 overhead, and transmits the DS3/E3 signal.
Refer to
Figure 10-37 for the location of the DS3/E3 Framer/Formatter blocks in the DS316x devices.
Figure 10-37. Framer Detailed Block Diagram
IEEE P1149.1
JTAG Test
Access Port
Microprocessor
Interface
HDLC
FEAC
LLB
DLB
DS3 / E3
Transmit
Formatter
DS3 / E3
Receive
Framer
Trail
Trace
Buffer
Tx Cell
Processor
Tx
FIFO
System
In
te
rfa
ce
Rx
Cell
Processor
Rx
FIFO
Tx Packet
Processor
SLB
Rx
Packet
Processor
TAIS
TUA1
TX
FRAC/
PLCP
RX FRAC/
PLCP
Clock
Rate
Adapter
TX BERT
RX BERT
PLB
ALB
UA1
GEN
B3ZS/
HDB3
Encoder
B3ZS/
HDB3
Decoder
10.10.2 Features
10.10.2.1 Transmit Formatter
Programmable DS3 or E3 formatter – Accepts a DS3 (M23 or C-bit) or E3 (G.751 or G.832) signal and
performs DS3/E3 overhead generation.
Arbitrary framing format support – Generates a signal with an arbitrary framing format. The line
overhead/stuff periods are added into the data stream using an overhead mask signal.
Generates alarms and errors – DS3 alarm conditions (AIS, RDI, and Idle) and errors (framing, parity, and
FEBE), or E3 alarm conditions (AIS and RDI/RAI) and errors (framing, parity, and REI) can be inserted into the
outgoing data stream.
Externally controlled serial DS3/E3 overhead insertion port – Can insert all DS3 or E3 overhead via a
serial interface. DS3/E3 overhead insertion is fully controlled via the serial overhead interface.
HDLC overhead insertion – An HDLC channel can be inserted into the DS3 or E3 data stream.
FEAC insertion – A FEAC channel can be inserted into the DS3 or E3 data stream.
Trail Trace insertion – Inputs and inserts the G.832 E3 TR byte.
10.10.2.2 Receive Framer
Programmable DS3 or E3 framer – Accepts a DS3 (M23 or C-bit) or E3 (G.751 or G.832) signal and performs
DS3/E3 overhead termination.
Arbitrary framing format support – Accepts a signal with an arbitrary framing format. The Line overhead/stuff
periods are removed from the data stream using an overhead mask signal.