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DS21354 & DS21554
76 of 117
COMPONENT
DESCRIPTION
D1 – D4
Schottky Diode, International Rectifier 11DQ04
C1
0.1uf ceramic in parallel with 10uf tantalum
C2
.47 uf, non polarized ceramic construction
Fuse
1.25A slo-blo, Littlefuse V2301.25
S
Semtech LC01-6, 6V low capacitance TVS
X1, X2
Transpower PT314, Low DCR
16.5 Receive Monitor Mode
When connecting to a monitor port a large resistive loss is incurred due to the voltage divider between the
E1 line termination resistors (Rt) and the monitor port isolation resistors (Rm) as shown in the Figure 16-
8. The receiver of the DS21354/554 can provide gain to overcome the resistive loss of a monitor
connection. This is typically a purely resistive loss/gain and should not be confused with the cable loss
characteristics of an E1 transmission line. Via the TEST3 register as shown in the table below, the
receiver can be programmed to provide both 12dB and 30dB of gain.
TYPICAL MONITOR PORT APPLICATION
Figure 16-8
RECEIVE MONITOR MODE GAIN
Table 16-4
TEST3 (Address = AC Hex) Register Value
Gain
72 Hex
12dB
70 Hex
30dB
PRIMARY
E1 TERMINATING
DEVICE
MONITOR
PORT JACK
E1 LINE
X
F
M
R
DS21X54
Rt
Rm
Rm
SECONDARY E1
TERMINATING
DEVICE