7
TWK351 Option
The TWK351 option permits light call-in on 2-conductor shielded cable.
See Figure 7 for wiring diagram.
Staff Station Equipment
Staff station equipment may include wall-or ceiling-mounted cone loud-
speakers, or horn-type loudspeakers (used to ensure clear, intelligible
communication in areas with relatively high noise levels). Figure 9 shows
a wiring diagram for a loudspeaker. To initiate calls, locations are provided
with call-origination switches. The voice call-in option may be used when
stations are equipped with a customer-supplied DPDT momentary switch.
Call-Origination Switches
Voice Call-In Option
– A customer-supplied double-pole, double throw,
momentary contact switch maybe used to connect a staff station speaker
to the call-in line when the switch is actuated. See Figure 8.
CA10A and CA11A
– These momentary, rocker-type Call Switches are
used to signal the control panel operator to establish communications
through a two-way speaker. The CA11A incorporates a privacy mode to
prevent monitoring. See Figure 10.
Appendix
General Wiring
Where possible, locate the MCP35A centrally, relative to the rooms being
served, in order to minimize the length of speaker cables. Orient the unit
so that the operator, program director, or other parties are able to see the
controls at all times. Provide adequate lighting and ventilation. Do not
locate the unit close to heat sources (radiators, warm air ducts, etc.), or a
wall which would impede air flow through or around it.
Wires
– Class II wiring may be used for all audio and annunciator lines.
Support cables to prevent sagging or strain. Keep wires clear of objects
that would subject them to heat, friction, or other abuse.
Use No. 22 AWG shielded pairs with insulated outer jacket for speaker lines.
Annunciator lines require a third wire, which usually is No. 22AWG insu-
lated wire with clear insulation. The number and type of wire running from
each room to the control center are dependent upon the type of speaker
operation required. See Table 1.
Figure 7 – Wiring Diagram: TWK351 Option
Figure 9 – Wiring Diagram: Loudspeaker (only)
Figure 8 – Wiring Diagram: Room Speaker with
Customer-Supplied Voice Call-In Switch
Figure 10 – Wiring Diagram: A: Model CA10A; B: Model CA11A
A.
B.
