P
P
r
r
o
o
-
-
B
B
e
e
l
l
L
L
t
t
d
d
T
T
e
e
c
c
h
h
n
n
i
i
c
c
a
a
l
l
m
m
a
a
n
n
u
u
a
a
l
l
H
H
U
U
-
-
F
F
r
r
e
e
e
e
w
w
a
a
y
y
R
R
a
a
n
n
g
g
e
e
S
S
y
y
s
s
t
t
e
e
m
m
U
U
s
s
e
e
r
r
G
G
u
u
i
i
d
d
e
e
1
1
1
1
1
1
A
A
n
n
a
a
l
l
o
o
g
g
u
u
e
e
a
a
u
u
d
d
i
i
o
o
(
(
i
i
n
n
c
c
l
l
u
u
d
d
i
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n
n
g
g
t
t
i
i
m
m
e
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-
-
c
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)
)
This causes the least problem as the signal spectrum is benign and the circuit
designs generally reject most unwanted signals. Some interference could occur if the
equipment contains processors, etc; so all screens are grounded at the point of entry.
Good quality cables with foil shields should be used with the shield carried through
from end to end, and connected to the chassis earth at the point of entry using a very
short tail.
D
D
a
a
t
t
a
a
a
a
n
n
d
d
C
C
o
o
n
n
t
t
r
r
o
o
l
l
S
S
i
i
g
g
n
n
a
a
l
l
s
s
Cable should be of good quality with a foil shield. This shield must make contact all
round at the entry to the mating connector body at both ends of the cable. Pro-Bel
equipment with control interfaces is fitted with ‘D’ type connectors and the shield is
grounded t othe chassis at the point of entry. The ‘D’ type shield should be of the
tinned type fitted with screw-locks and with dimples on the male part. Ribbon cables
are NOT suitable under any circumstances outside the equipment frames.
O
O
t
t
h
h
e
e
r
r
s
s
i
i
g
g
n
n
a
a
l
l
f
f
o
o
r
r
m
m
a
a
t
t
s
s
MADI and binary high-bit-rate telecom signals should be treated as digital video.
Other telecom signals, eg HDB3 signals at 34Mbit/s, 8448 and 2048kbit/s are more
akin to analogue video, but the presence of high frequency clock signals inside the
frame is more likely. The installation of telecom equipment may require reference to
telecom standards. These usually use unbalanced BNC connections, but occasionally
balanced 120
W
circuits will be used, and should be treated as AES3.
Other balanced signals such as X21 (64,128,384,728 and 2048kbit/s) should be
treated as RS422/V11 control ports, and generally use 'D' type connectors.
M
M
a
a
i
i
n
n
s
s
All Pro-Bel equipment has the mains earth connected to the chassis at the point of
entry, which reduces EMC emissions.
