DS2149

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SR (B010101): Status Register

MSb

LSb

—

—

DFMO

—

QRSS

AIS

NLOOP

RCL

SYMBOL

POSITION

FUNCTION

—

SR.7

—

—

SR.6

—

DFMO

SR.5

Set when transmitter detects open circuit.

—

SR.4

—

QRSS

SR.3

Set when the QRSS pattern is present at the receiver.

AIS

SR.2

Set when the AIS pattern is present at the receiver.

NLOOP

SR.1

Set when the in-band loop-up code is present at the receiver.

RCL

SR.0

Set when receiver has detected consecutive s set forth by CR4.2.

Cleared when the receiver detects 14 1s in a window of 112 clock

cycles.

IR (B010110): Information Register

MSb

LSb

RL3

RL2

RL1

RL0

LUP

LDN

TSCD

LOTC

SYMBOL

POSITION

FUNCTION

RL3

IR.7

—

RL2

IR.6

—

RL1

IR.5

—

RL0

IR.4

—

LUP

IR.3

Set when in-band loop-up code is being received.

LDN

IR.2

Set when in-band loop-down code is being received.

TSCD

IR.1

Set when transmitter detects a short circuit.

LOTC

IR.0

Set when TCLK has not transitioned for approximately 5

ms.

Receive Level Indication: RL0 is the LSB and RL3 is the MSB of a 4-bit nibble that is used to indicate the inbound

signal strength. Convert the binary to decimal and multiply by -2.5dB. The result indicates the approximate

attenuation seen at the receiver inputs.