Ericsson LBI-39076B - Manual (Page 18)

LBI-39076B INSTALLATION
18
6. GTI TELEPHONE INTERFACE
The 6th step to install the ELI option is to configure
each GTI telephone interface to match the type of telephone
circuit to be connected to it. The first Main boards,
identified by the manufacturer’s number 702-9588A, are
configured differently than the later Main boards, identified
by the manufacturer’s number 702-9588D or E. The boards
are referred to as revision-A Main boards and revision-D or
E Main boards respectively.
Revision A Main boards do not support Direct
Inward Dial (DID) telephone lines. If you need
to have a DID telephone line connected to a GTI
unit, that GTI unit must contain a revision-D or
later Main board.
NOTE
Revision-A Main Board
The revision-A Main board uses 15 jumpers (JP1
through JP15) and two fuses (F2 and F3) to configure the
telephone interface. Set the jumpers and fuses to match the
type of circuit to be connected to it. Figure 18 shows the
locations of these jumpers and fuses on the revision-A Main
board, and Table 2 lists the jumper and fuse configurations
for four common types of telephone circuits. Figure 19
through Figure 22 show simplified schematics of these four
configurations.
Many other configurations of the GTI telephone
interface are possible. Table 3 shows which jumpers and
fuses to use to obtain each specific interface characteristic.
Figure 23 shows a simplified schematic of the interface,
including key components and the location of each jumper
and fuse. If a jumper or fuse is not specifically required for
a characteristic, remove it. Not all characteristics are
compatible with each other. For example, the interface
cannot be configured for a -48 V reference for the E-Lead
and at the same time be configured for an external reference
for the M-Lead.
Be careful of terms when talking or reading about the
telephone circuit that the GTI unit is to interface. Terms
such as send, receive, in, out, E-Lead, and M-Lead are
sometimes defined differently by different people and from
different points of reference. The terms used in this manual
are defined as follows:
•
4-Wire Send - audio voice signals from GTI unit to
telephone circuit.
•
4-Wire Rec - audio voice signals from telephone
circuit to GTI unit.
•
M-Lead - telephone circuit supervision signal from
GTI unit to telephone circuit.
•
E-Lead - telephone circuit supervision signal from
telephone circuit to GTI unit.
JP1
JP2 JP3
JP4
JP5
JP6
RJ-45
Telephone Line
Connector
JP7
JP8
JP9
JP10
JP11
JP12 JP13
JP14 JP15
F3 F2
C
B A
D
E
F
M
B B D D
A
A
C C C
B
A
D
M
B
C
A
B
A
B
A
B
A
B
A
Figure 18 - Jumper Locations (Rev A Main Board)
Table 2 - Configurations by Line Type (Rev A Main Board)
TELEPHONE JUMPER POSITIONS FOR JP1 THROUGH JP15 FUSES
LINE TYPE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 F2&F3
End-to-End Loop Start - B B - - - - A B - - - A A A OUT
End-to-End Ground Start D+M B B - - - - B A - - B A A A IN
4-Wire E&M, Microwave E A+C A+C IN IN C+M - - - IN IN A - B B OUT
4-Wire E&M, Type I E A+C A+C - - C+M - - - IN IN B - B B IN