DS33R11 Ethernet Mapper with Integrated T1/E1/J1 Transceiver

10.5 E1 Framer/Formatter Control and Status

The E1 framer portion of the transceiver is configured by a set of four control registers. Typically, the control registers are only accessed when the system is first powered up. Once the device has been initialized, the control registers need only to be accessed when there is a change in the system configuration. There are two receive control registers (TR.E1RCR1 and TR.E1RCR2) and two transmit control registers (TR.E1TCR1 and TR.E1TCR2). There are also four status and information registers. Each of these eight registers is described in this section.

Table 10-3. E1 Sync/Resync Criteria

FRAME OR

SYNC CRITERIA

RESYNC CRITERIA

MULTIFRAME

LEVEL

 

 

 

 

Three consecutive incorrect

 

FAS present in frame N and

FAS received

 

Alternate: (TR.E1RCR1.2 = 1)

FAS

N + 2; FAS not present in

 

frame N + 1

The above criteria is met or

 

 

three consecutive incorrect bit

 

 

2 of non-FAS received

CRC4

Two valid MF alignment

915 or more CRC4 codewords

words found within 8ms

out of 1000 received in error

 

 

Valid MF alignment word

Two consecutive MF alignment

CAS

found and previous time slot

16 contains code other than

words received in error

 

 

all 0s

 

ITU SPEC.

G.706

4.1.1

4.1.2

G.706

4.2 and 4.3.2

G.732

5.2

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Maxim DS33R11 specifications 10.5 E1 Framer/Formatter Control and Status, E1 Sync/Resync Criteria, ITU Spec