EFJohnson 3000 SERIES - Manual (Page 137)

TELEPHONE INTERFACE MODULE (TIM)
14-27
14.11.6 FINAL PATH INSPECTION
If all of the mechanical assembly has been made
properly, the connections in Table 14-11 should exist.
14.12 BACKGROUND INFORMATION
14.12.1 STANDARD SIGNAL
The standard signal is defined as a 1 kHz audio
tone modulated to
±
2 kHz deviation, with data modu-
lated to
±
1 kHz (total deviation is
±
3 kHz).
14.12.2 OUTLINED OBJECTIVE
The specific technical purposes of tuning the
repeater and 4-Wire E&M are to ensure:
1. The RF hardware is properly tuned.
2. Data levels (LTR and high speed) are properly set,
both in/out of the Radio Concentrator.
3. In dispatch mode, Audio In = Audio out of the
repeater.
4. Levels transmitted to and received from the CO are
given adequate gain.
5. The hybrids interfacing system equipment to the CO
are properly balanced.
6. The links all have unit gain across them.
7. Interconnect and Dispatch audio are at the same
level (in terms of Exciter deviation).
The purpose of tuning the Switch is to ensure all
audio coming into the Switch, either from an RF
channel, a Telco resource, or a Network Link, bus at
the same level. In other words, regardless of where
audio originates, the amplitude is the same level in the
Switch. Once achieved, the Switch directs the audio
in from any resource out to any other resource with all
the proper levels.
Standard audio received from a mobile is defined
in terms of
±
2 kHz of audio deviation (
±
3 kHz total).
Defining standard audio from the Central Office (CO)
is not as simple. It ranges from -10 to -30 dBm,
depending on distance from the CO and line quality.
One objective of the tuning procedure is to determine
the level of average audio from the CO, and to
normalize that level.
Tuning the system ensures that
±
2 kHz of audio
received from a mobile results in the same level on the
backplane as does the CO standard level.
Once the levels are properly set,
±
2 kHz of audio
deviation is injected into the receiver and
±
2 kHz of audio deviation is transmitted from the
Exciter (dispatch). Also, standard audio coming in
from the CO results in
±
2 kHz of audio deviation trans-
mitted from the Exciter (interconnect). Finally,
±
2
kHz of audio deviation injected into the Receiver
results in a standard audio level transmitted to the CO.
14.12.3 THE ORDER OF THINGS
First, properly tune the RF equipment. Next, the
repeater (dispatch) channels.
±
2 kHz of audio in, gives
±
2 kHz of audio out.
Table 14-11 E&M TO TERMSET
CONNECTIONS
SLOT 1
6132/Backplane [1] J3 [2] E&M DB-15 [3]
Pin # Signal Pin # Signal Pin #
41
47
7
13
21
23
Tx Tip
Tx Ring
Rx Tip
Rx Ring
M-Lead
E-Lead
26
1
27
2
29
28
Rx +
Rx Gnd
Tx +
Tx Gnd
E-Lead
M-Lead
1
6
8
10
13
14
SLOT 2
6132/Backplane [1] J3[2] E&M DB-15 [3]
Pin # Signal Pin # Signal Pin #
41
47
7
13
21
23
Tx Tip
Tx Ring
Rx Tip
Rx Ring
M-Lead
E-Lead
30
5
31
6
33
32
Rx +
Rx Gnd
Tx +
Tx Gnd
E-Lead
M-Lead
1
6
8
10
13
14
[1] Information from Page 10 of 6132 handout,
corresponds to page 5 of rack handout.
[2]
Information from Page 4 (Table 3) of rack handout.
[3] Information from E&M card schematics.