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

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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