DS3181 Maxim Integrated Products, DS3181 Datasheet - Page 179

• Manufacturer Part Number: DS3181
• Description: Network Controller & Processor ICs DS3-E3 ATM-Packet PH Y with Built-in Line
• Manufacturer: Maxim Integrated Products

Specifications of DS3181

• Product: Framer
• Number Of Transceivers: 1
• Data Rate: 44.736 Mbps
• Supply Voltage (max): 3.465 V
• Supply Voltage (min): 3.135 V
• Supply Current (max): 280 mA
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Package / Case: TEBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DS3181/DS3182/DS3183/DS3184
10.10.8.5 Transmit G.832 E3 AIS Generation
G.832 E3 AIS generation overwrites the data stream with AIS. If transmit AIS is enabled, the data stream (payload
and E3 overhead) is forced to all ones.
10.10.8.6 Receive G.832 E3 Frame Processor
The G.832 E3 frame format is shown in
Figure
10-44. FA1 and FA2 are the Frame Alignment bytes. EM is the Error
Monitoring byte used for path error monitoring. TR is the Trail Trace byte used for end-to-end connectivity
verification. MA is the Maintenance and Adaptation byte used for far-end path status and performance monitoring
(See
Figure
10-45). NR is the Network Operator byte allocated for network operator maintenance purposes. GC is
the General-Purpose Communications Channel byte allocated for user communications purposes.
10.10.8.7 Receive G.832 E3 Framing
G.832 E3 framing determines the G.832 E3 frame boundary. The frame boundary is found by identifying the frame
alignment bytes FA1 and FA2, which have a value of F6h and 28h, respectively. The framer is an off-line framer
that updates the data path frame counters when an out of frame (OOF) condition has been detected. The use of an
off-line framer reduces the average time required to reframe, and reduces data loss caused by burst error. The
G.832 E3 framer checks each bit position for the frame alignment word (FA1 and FA2). The frame boundary is set
once the frame alignment word is identified. Since, the frame alignment word check is performed one bit at a time;
up to 4296 checks may be needed to find the frame boundary. The data path frame counters are updated if an
error free frame alignment word is received for two additional frames, and an OOF condition is present.
10.10.8.8 Receive G.832 E3 Performance Monitoring
Performance monitoring checks the E3 frame for alarm conditions and errors. The alarm conditions detected are
OOF, LOF, COFA, LOS, AIS, RUA1, and RDI. The errors accumulated are framing, parity, and Remote Error
Indication (REI) errors. An Out Of Frame (OOF) condition is declared when four consecutive frame alignment
words (FA1 and FA2) contain one or more errors, when 986 or more frames out of 1,000 frames has a BIP-8 block
error, or at the next framing word check when a manual reframe is requested. An OOF condition is terminated
when three consecutive frame alignment words (FA1 and FA2) are error free or the G.832 E3 framer updates the
data path frame counters.
A Loss Of Frame (LOF) condition is declared by the LOF integration counter when it has been active for a total of T
ms. The LOF integration counter is active (increments count) when an OOF condition is present, it is inactive (holds
count) when an OOF condition is absent, and it is reset when an OOF condition is absent for T continuous ms. T is
programmable (0, 1, 2, or 3). An LOF condition is terminated when an OOF condition is absent for T continuous
ms.
A Change Of Frame Alignment (COFA) is declared when the G.832 E3 framer updates the data path frame
counters with a frame alignment that is different from the current data path frame alignment.
A Loss Of Signal (LOS) condition is declared when the HDB3 encoder is active, and it declares a LOS condition. A
LOS condition is terminated when the HDB3 encoder is inactive, or it terminates a LOS condition.
An Alarm Indication Signal (AIS) condition is declared when 7 or less zeros are detected in each of two consecutive
frame periods that do not contain a frame alignment word. An AIS condition is terminated when 8 or more zeros are
detected in each of two consecutive frame periods.
A Receive Unframed All 1’s (RUA1) condition is declared if in each of 4 consecutive 2047 bit windows, five or less
zeros are detected and an OOF condition is continuously present. A RUA1 condition is terminated if in each of 4
consecutive 2047-bit windows, six or more zeros are detected or an OOF condition is continuously absent.
A Remote Defect Indication (RDI) condition is declared when four consecutive frames are received with the RDI bit
(first bit of MA byte) set to one. An RDI condition is terminated when four consecutive frames are received with the
RDI bit set to zero.
Three types of errors are accumulated, framing, parity, and Remote Error Indication (REI) errors. Framing errors
are determined by comparing FA1 and FA2 to their expected values. The type of framing errors accumulated is
programmable (OOF, bit, byte, or word). An OOF error increments the count whenever an OOF condition is first
detected. A bit error increments the count once for each bit in FA1 and each bit in FA2 that does not match its
expected value (up to 16 per frame). A byte error increments the count once for each FA byte (FA1 or FA2) that
does not match its expected value (up to 2 per frame). A word error increments the count once for each FA word
(both FA1 and FA2) that does not match its expected value (up to 1 per frame).
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