5
X
RS-232,485 + 2
X
E
THERNET
/2 M
BIT
/
S
G.703 (G.704) M
ULTIPLEXER
O
PERATING
M
ANUAL
IOA81-1E
20
August 2004
4.4 Selection of input and output impedance of line ports
To adjust the multiplexer to operation with balanced cables (impedance of 120
Ω
) or co-
axial cables (impedance of 75
Ω
), the JP1, JP2-4 , JP5-7, JP8-11, JP12-15, and JP16 jumpers
(positions 4 and 5) should be set as shown in the table on Fig. 22.
Jumpers are accessible after removing the cover. To get the access to jumpers one should
undo four screws from the top of housing, then undo four side screws and remove upper
cover.
The value of characteristic impedance can be set up for each port individually. The multi-
plexer is factory set for operation with balanced cables with the impedance of 120
Ω
.
JP1
]120[
] 75 [
1
2
3
JP8-11
1
2
3
JP2-4
] 75 [
]120[
3
2
1
JP5-7
3
2
1
3
2
1
JP12-15
JP5-7
JP1
JP12-15
JP 16(p.4)
1-2 2-3
1-2 2-3
1-2 2-3
120
75
Ω
Ω
(factory setting)
PMC
PMC
AL
TERA
ATMEL
17 3 4 5
RESET
J 16
P
Shorted Open
PORT A
JP2-4
JP1
JP8-11
JP 16(p.5)
1-2 2-3
1-2 2-3
1-2 2-3
120
75
Ω
Ω
(factory setting)
Shorted Open
PORT B
Fig. 22.
Location of jumpers on the multiplexer’s board carrying line interfaces
