IDT82P2284 QUAD T1/E1/J1 LONG HAUL / SHORT HAUL TRANSCEIVER
Functional Description 12 March 22, 2004
3 FUNCTIONAL DESCRIPTION
The IDT82P2284 is a highly featured single device solution for T1/
E1/J1 trunks. Each link of the IDT82P2284 can be independently config-
ured. The configuration is performed through an SPI or parallel micro-
processor interface.
LINE INTERFACE - RECEIVE PATH
In the receive path, the signals from the line side are coupled into
the RTIPn and RRINGn pins and pass through an Impedance Termina-
tor. An Adaptive Equalizer is provided to increase the sensitivity for small
signals. Clock and data are recovered from the digital pulses output from
the slicer. After passing through the Receive Jitter Attenuator (can be
enabled or disabled), the recovered data is decoded using B8ZS (for T1/
J1) / HDB3 (for E1) or AMI line code rules and clocked into the Frame
Processor. Loss of signal, line code violations and excessive zero are
detected.
FRAMER - RECEIVE PATH
In T1/J1 Mode, the recovered data and clock of each link can be
configured in Super Frame (SF), Extended Super Frame (ESF), T1 Digi-
tal Multiplexer (DM) or Switch Line Carrier - 96 (SLC-96) formats. (The
T1 DM and SLC-96 formats only exist in T1 mode). The framing can also
be bypassed (unframed mode). The Framer detects and indicates the
out of SF/ESF/DM/SLC-96 synchronization event, the Yellow, Red and
AIS alarms. The Framer also detects the presence of inband loopback
codes and bit-oriented messages. Frame Alignment Signal errors, CRC-
6 errors, out of SF/ESF/T1 DM/SLC-96 events and Frame Alignment
position changes are counted. Up to three HDLC links (in ESF and T1
DM format) or two HDLC links (in SF and SLC-96 format) are provided
to extract the HDLC message on the DL bit (in ESF format) / D bit in
CH24 (in T1 DM format) or any arbitrary position. In the T1/J1 receive
path, signaling debounce, signaling freeze, idle code substitution, digital
milliwatt code insertion, idle code insertion, data inversion and pattern
generation or detection are supported on a per-channel basis. An Elastic
Store Buffer that supports controlled slip and adaptation to backplane
timing may be enabled. In the Receive System Interface, various operat-
ing modes can be selected to output signals to the system.
In E1 Mode, the recovered data and clock of each link can be con-
figured to frame to Basic Frame, CRC Multi-Frame and Signaling Multi-
Frame. The framing can be bypassed (unframed mode). The Framer
detects and indicates the following event: out of Basic Frame Sync, out
of CRC Multi-Frame, out of Signaling Multi-Frame, Remote Alarm Indi-
cation signal and Remote Signaling Multi-Frame Alarm Indication signal.
The Framer also monitors Red and AIS alarms. Basic Frame Alignment
Signal errors, Far End Block Errors (FEBE) and CRC errors are
counted. Up to three HDLC links are provided to extract the HDLC mes-
sage on TS16, the Sa National bits or any arbitrary timeslot. In the E1
receive path, signaling debounce, signaling freezing, idle code substitu-
tion, digital milliwatt code insertion, trunk conditioning, data inversion
and pattern generation or detection are also supported on a per-timeslot
basis. An Elastic Store Buffer that supports slip buffering and adaptation
to backplane timing may be enabled. In the Receive System Interface,
various operating modes can be selected to output signals to the sys-
tem.
SYSTEM INTERFACE
On the system side, if the device is in T1/J1 mode, the data stream
of 1.544 Mbit/s can be converted to/from the data stream of 2.048 Mbit/s
by software configuration. In addition, the four links can be grouped into
one set. The set can be multiplexed to or de-multiplexed from one of the
two 8.192 Mbit/s buses. If the device is in E1 mode, the four links can be
multiplexed to or de-multiplexed from one of the two 8.192 Mbit/s buses.
FRAMER - TRANSMIT PATH
In the transmit path, the Transmit System Interface inputs the sig-
nals with various operating modes. In T1/J1 mode, the signals can be
processed by a Transmit Payload Control to execute the signaling inser-
tion, idle code substitution, data insertion, data inversion and test pattern
generation or detection on a per-channel basis. The transmit path of
each transceiver can be configured to generate SF, ESF, T1 DM or SLC-
96. The framer can also be disabled (unframed mode). The Framer can
transmit Yellow alarm and AIS alarm. Inband loopback codes and bit ori-
ented message can be transmitted. Up to three HDLC links (in ESF and
T1 DM format) or two HDLC links (in SF and SLC-96 format) are pro-
vided to insert the HDLC message on the DL bit (in ESF format) / D bit in
CH24 (in T1 DM format) or any arbitrary position. After passing through
a Transmit Buffer, the processed data and clock are input to the
Encoder.
In E1 mode, the signals can be processed by a Transmit Payload
Control to execute the signaling insertion, idle code substitution, data
insertion, data inversion and test pattern generation or detection on a
per-timeslot basis. The transmit path of each transceiver can be config-
ured to generate Basic Frame, CRC Multi-Frame and Signaling Multi-
Frame. The framer can be disabled (unframed mode). The Framer can
transmit Remote Alarm Indication signal, the Remote Signaling Multi-
Frame Alarm Indication signal, AIS alarm and FEBE. Three HDLC links
are provided to insert the HDLC message on TS16, the Sa National bits
or any arbitrary timeslot. The processed data and clock are input to the
Encoder.
LINE INTERFACE - TRANSMIT PATH
The data is encoded using AMI or B8ZS (for T1/J1) and HDB3 (for
E1) line code rules. The Transmit Jitter Attenuator, if enabled, is pro-
vided with a FIFO in the transmit data path. A de-jittered clock is gener-
ated by an integrated digital phase-locked loop and is used to read data
from the FIFO. The shapes of the pulses are user programmable to
ensure that the T1/E1/J1 pulse template is met after the signal passing
through different cable lengths and types. Bipolar violation can be
inserted for diagnostic purposes if AMI line code rule is enabled. The
signal is transmitted on the TTIPn and TRINGn pins through an Imped-
ance Terminator.