ACCURATE ELECTRONICS INC
Practice Section 104003C Rev A January 2014
PO BOX 1654 97075-1654 8687 SW HALL BLVD 97008 BEAVERTON OR USA 503.641.0118 FAX 503.646.3903
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4
TONE-LOOPBACK FREQUENCY
3.09
Tone-loopback frequency is selected by means of 10-position DIP
switch (S3) located on the 104003C’s daughter pcb. Only 1 switch position
is required to select any 1 of 11 available frequencies. The available loopback
frequencies and settings of switch
S3
are summarized in Table 3.
Table 3.
Loopback Frequency Selection.
FREQUENCY
(Hz)
S3 SWITCH POSITION
SET TO
ON
*
2813
All switch positions OFF
2713
1
2513
2
2413
3
1913
4
1813
5
1713
6
1613
7
1513
8
1413
9
1313
10
*all other S13 switch positions MUST be set to the OFF position.
LOOPBACK LEVELS
3.10
Loopback levels of +16, +9, -16, or –23dB are selected via DIP switch
S4
, located on the 104003C’s daughter pcb. Loopback level options are
described in paragraph 2.10; the various settings of switch
S4
are summarized
in Table 4.
Table 4.
Loopback Level Selection.
Loopback Levels
Switch Positions
S4-1
S4-2
+16dB
Off
Off
+9dB
Off
On
-16dB
On
Off
-23dB
On
On
ALIGNMENT
3.11
This alignment subsection is divided into two parts: preliminary
alignment and final alignment verification. In the preliminary alignment
procedure, impedance options are selected, equalization is introduced into the
receive and the transmit channel (if required), and gain or attenuation is
introduced in both the transmit and the receive channel to match the
transmission levels specified on the circuit level record (CLR) card. In the
final alignment verification procedure, the 104003C is placed into service and
end-to-end transmission measurements are made. If the measured levels
differ from those specified on the CLR card, the front-panel TX and RX
LEVEL switches are adjusted to provide the specified levels.
Note:
Two condensed preliminary alignment procedures (Figures 6 and 8)
and two condensed final alignment verification procedures (Figures 7 and
9) may be used to facilitate alignment of the 104003C module.
PRELIMINARY ALIGNMENT
3.12
Refer to the CLR card for the required facility port and terminal port
impedances. In general, the 1200-ohm option is used to interface loaded
cable, the 600-ohm option is used to interface nonloaded cable, carrier,
station apparatus, or SF signaling units, and the 150-ohm option is used to
interface short segments of nonloaded cable in applications where a small
degree of slope equalization is required. Use S2 (Main Board) to set the
facility port impedance and S4 (Main Board) to set the terminal port
impedance.
FIGURE 5.
Module Switch Locations.