20(57)
Date Rev
DocumentnumberPrepared
Doc respons/Approved Checked File/Reference
1999-07-15 V
1531-BDV 113 08 Uen
INSTALLATION INSTRUCTION
Subject responsible
5.9.2 DIP-switches in positions 198 and 199
Selection of ground strapping for the coax 75 Ω or se-
lection of the 120 Ω twisted pair interface.
On factory delivery the switches are set to OFF-posi-
tion = no ground thus enabling 120 Ω interface with a
twisted pair cable. These DIP-switches connect the
75 Ω interface coax screen to ground, either directly to
0Vorviaa1nFcapacitor. DIP-switch 198 switches the
receiver and 199 the transmitter side. The screen shall
normally be grounded on the transmitter side. Normal-
ly, the screen on the reception side is not connected to
ground. Refer to local market requirements
Ranges on the interface of the BTU-D
This interface covers the short distance to the next NT
or Line Terminating Unit as the end point of a public or
private network. The range is only defined in terms of
the covered attenuation by the interface that is 6 dB. If
required choose cables with low attenuation to achieve
a maximum distance.
For ranges exceeding 6 dB attenuation additional digit-
al data transmission equipment is required. Line Ter-
minating Unit (LTU) ASB 501 04 is available for such
purposes.
Some markets (e.g. Austrian PTT) require the use of a
double-shielded interface cable. The outer shield
should be connected to frame earth and the inner
shield should be connected to 0V on the board. A 20 m
long standard cable is available with the ERICSSON
ordering number TSR 901 0481/20000.
198/1
199/1
198/2
199/2
FUNCTION
OFF OFF
120 Ω connection
1)
1. ) Factory setting
OFF ON screen connected to ground
ON OFF screenconnected to ground
via 1nF capacitor
d1
d1 - The line length depends on cable type used. The board
Line terminating unit BTU-D
Coax 75
Ω and twisted pair 120 Ω interface
attenuation at 1,024 MHz per 100m.
allows 6 dB cable attenuation at 1.024 MHz. Check cable
26
28
30
32
C
18
20
22
24
A
RING_OUT
RING_IN
TIP_OUT
TIP_IN
19
23
LA1
LB1
LA2
LB2
0 V
Outgoing
Incoming
Connection field 6
wires
wires
Connection for 75 Ω
coaxial cable
Connection for
120 Ω twisted pairs
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