Section 365–336–202
8
Option
Use to
Position
S9 (MLB)
front-pan-
el push-
With each operation of switch S9,
the channel unit alternates be-
tween manual loopback and nor-
To manually activate Loopback (MLB).
el ush
button
tween manual loo back and nor
mal operating mode. Manual
loopback mode overrides the op-
tioning of S8.
To manually release Loopback (MLB).
S10
––––––––
Not used
S11–1
(T SIG)
OFF
For 8-bit encoding.
(T–SIG)
ON
For 7 5/6 encoding. (Normal mode)
S11–2
(R SIG)
OFF
For 8-bit decoding.
(R–SIG)
ON
For 7 5/6 decoding. (Normal mode)
8.
ALIGNMENT
8.1
Transmit Alignment
The XMT ATTN switches S2 and S3 are prescription controls that provide attenuation from 0.0 to 32.5dB in incre-
ments of 0.1dB to accommodate an input TLP range from –19.5 to 13.0dBm. To adjust the transmit path to the
proper operating level, the difference between –19.5 and the transmit TLP at T&R must be obtained:
XMT ATTN = TLP – (–19.5)
Use Table 2 for common TLP values.
For example, for a 0 db transmit TLP, set the sum of S2 and S3 to 19.5 by placing the switch sections shown be-
low in the ON position.
2 4 8 16
1
.2.4.8
.1
O
N
S2
O
N
S3
ON
16 + 2 + 1 + 0.4 + 0.1 = 19.5
XMT ATTN (DB)
8.2
Receive Alignment
The RCV ATTN switches S4 and S5 are prescription controls that provide attenuation from 0.0 to 32.5dB in incre-
ments of 0.1dB to accommodate an output TLP range from +13.0 to –19.5dBm. To adjust the receive path to the
proper operating level, the difference b13.0 and the receive TLP at T1 & R1 must be obtained:
RCV ATTN = 13.0 – TLP
Use Table 3 for common TLP values.
For example, for a 0 db receive TLP, set the sum of S4 and S5 to 13 by placing the switch sections shown below
in the ON position.
2 4 8 16
1
.2.4 .8
.1
O
N
S4
O
N
S5
ON
8 + 4 + 1 = 13
RCV ATTN (DB)
8.3
Equal Level Loopback (ELL) Alignment
The ELL switches S6 and S7 are prescription controls that provide adjustment to match the RCV path output to
the XMT path input. Perform the ELL alignment as follows: