Datasheet

73M1866B/73M1966B Data Sheet DS_1x66B_001
78 Rev. 1.6
12 Loopback and Testing Modes
Figure 39 shows the six loop back modes available within the 73M1x66B.
TBS
DSDM
PRM SCM
MSBI
LSBI
RxAFE
SinC3
Filter
Onchip
LIC
SPI
Interface
PCM
Interface
TxAFE
Interp.
Filter
Decim.
Filter
TxData
RxData
RBS
Tip
Ring
PRP SCP
TxD
RxD
CTL
STA
External
LIC
73M1906B
73M1916
Aux A/D
STA
ALB
INTLB1
DIGLB2
DIGLB1
INTLB2
RxA
TxA
PCMLB
Figure 39: Loopback Modes Highlighted
Table 41 describes how the above control bits interact to provide each of the six loopback modes.
Table 41: Loopback Modes
TEST
TMEN
DTST
LB
Loopback Mode
Mnemonic
0000 0 00 0
Normal Mode. (Default) No Loops
0000 0 00 1
Loopback between PCM Compander
and FXO core.
PCMLB
0000 1 10 0
Digital Loopback Mode
Interpolated TxData (TxD) is looped
back to the Decimated RxData input
(RxD).
DIGLB1
0000 1 11 0
Remote Analog Loopback
Received RxD is looped back as TxD
and transmitted back to the
73M1x66B
Line-Side Device; RxD is D/A
converted to yield the analog transmit
signal (TxA).
INTLB1
0001 0 00 0
Digital Loopback Mode
DR Transmit Bit Stream (TBS) is
looped back to receive digital channel
and received at DX (DIGLB2).
DIGLB2
0010 0 00 0
Remote Analog Loopback
Receive analog signal is converted to
Received Bit Stream (RBS) and is
looped back to TBS and the analog
transmit channel (INTLB2).
INTLB2
0011 0 00 0
Analog Loopback
The transmit DR data is connected to
the receiver at the analog interface
and received at the DX pin (ALB).
ALB