Table of Contents
Advertisement
B
ACKPLANE
The HRE-425 List 1 Backplane shown in
•
trace connections to each of the 12 card-edge connectors (J1 through J12)
•
terminal block connections to TB1
•
25-pair, multiple connectors (P1, P2, P3, and P4)
12
P
G
OWER AND
ROUNDING
12 numbered, backplane printed circuit traces connect the HRE-425 frame ground to the chassis
ground, pin 1, of every slot, which is the normal connection. The trace can be cut to disconnect
the HRE-425 frame ground from pin 1 of any slot. This permits the HRE-425 to support plugs
which use pin 1 for other purposes than frame ground. (These traces have no effect on pin 27,
which always remains connected to frame ground of the shelf.) The area where the trace may
be safely cut is identified by a small rectangle. See
their corresponding slot number, either below or above the rectangle.
ADC recommends that pin 4 of TB1, frame ground, be connected to earth ground according to the grounding
recommendations found in Section 9 of Bellcore's GR-1089-DEC, 1996 (see
properly ground the enclosure could result in the following adverse situations:
•
bit errors due to the inability of the ungrounded case to attenuate the noise inducing energy from stray EMI
fields
•
bit errors due to crosstalk from adjacent communication equipment
6
Figure 4
J12-J1
9
8
10
11
P1
P3
P2
Figure 4. HRE-425 List 1 Backplane
September 22, 1999
can be connected in one of the following ways:
2
3
6
7
5
4
Frame ground trace
P4
Figure
4. These locations are numbered with
150-425-100-04
F1-F12
1
Tb1
H0335-A
Figure 6 on page
8). Failure to
HRE-425 List 1
Advertisement
Table of Contents
