INSTALLATION
Analog Input
Fine Level
Adjustments
The analog sections in both transmit and receive directions have ad-
justments to fine tune the signal amplitude to compensate for installa-
tions where the input levels are not within the –16 to + 0 dB range or when
excessive output cable lengths require greater than nominal signal drive.
The amplitude of the input transmit signal to the transmit circuit can be
adjusted in 0.5 dB steps in the range –6.0 to +1.5 dB (approximately a 0 to
–16 dBm transmit level selection) by DIP switches S1-2, S1-3, S1-4 and S1-
5. Refer to Table 2-10 for setting of the DIP switches.
Similarly, the amplitude of the output receive signal from the receive cir-
cuit can be adjusted in 0.5 dB steps in the range –6.0 to +1.5 dB
(approximately a 0 to + 7 dBm receive level selection) by software via the
TMS/supervisory controller.
For instructions on how to align the levels, refer to Appendix D, CELP
Circuit Voice Level Testing.
TABLE 2-10. OPTION SELECTIONS, INPUT LEVEL ADJUSTMENT
S1-2
S1-3
S1-4
S1-5
Input
(–2 dB)
(+1 dB)
(–4 dB)
(+0.5 dB)
Compensation
Application
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
+1.5 dB
+1.0 dB
+0.5 dB
0.0 dB
–0.5 dB
–1.0 dB
–1.5 dB
–2.0 dB
–2.5 dB
–3.0 dB
–3.5 dB
–4.0 dB
–4.5 dB
–5.0 dB
–5.5 dB
–6.0 dB
Switches S1-2 through S1-5 select attenuation
or amplification for the voice input level. This
compensates for cable losses or improper
output levels from connected telephone
equipment. The switch selects a level of
compensation from +1.5 dB to –6.0 dB, in 0.5
dB steps. Each segment of switch S2 selects a
level of attenuation or amplification; the
individual steps are added to produce a
particular level. A level is selected to
compensate for some measured deviation of
the output level of equipment connected to the
channel. The deviation is the difference
between the actual level and the nominal level
of 0 dBm or –16 dBm selected on switch S1-1.
For example, if the nominal level is 0 dBm, and
the actual level is +2 dBm, selection of –2 dB
would compensate for the difference between
the nominal and measured input values.
2-10
