PETS-2 Crossing Telephone System
QUICKFIX INSTALLATION HANDBOOK
Page 11
of 40
Issue 2
13/12/99
11
4.2 Signal Box Unit
Figure 1 - Photograph of Signalbox Unit
The Signal Box unit is designed for wall mounting, although it may sometimes be adapted
for rack mounting. The casing of Signal Box and Level Crossing units are identical, but the
front panel arrangements are entirely different.
On the Signal Box units, the front panel comprises a membrane / label front laminated onto
a 4mm aluminium plate. This is fitted ‘inside’ the case edges, allowing the panel to be
recessed more than the Level crossing arrangement. This recessing enables the buttons
(on the cards within) to be activated through the front membrane. This presents a smooth,
wipe clean front panel, with the advantage of having ‘real’ push buttons. Unused button
locations are protected by a supporting disk behind the membrane, at each unused location
(Lines 2,3 & 4 on a standard Signal Box Unit).
4.2.1 Item 1 - Connection Plate
Shown in the photograph (Fig. 1) without connectors and Connector Retention bracket. All
of the connections to PETS are made through plug/ socket ‘D’ type connectors to the left
hand side of the unit. On the Signal Box unit, these connectors are not environmentally
sealed. However, the connector arrangements are novel as their right angle shells are used
Item 3
Frame Retention bolt
Item 5
Front panel
Item 1
Connection
Plate
Connector retention
bracket, upper fixing screw.
