Installation and Maintenance Manual
Control Circuitry
The control circuitry in the CommCenter has a built-in priority level feature. If a message is already
sounding when a higher priority message is activated, the higher priority message automatically
overrides the lower priority message. When the higher priority message is deactivated, the lower priority
message is initiated as long as it is still activated. The messages are prioritized with Priority Tone 1
having the highest priority down to Priority Tone 6. The cascade input has the lowest level of priority.
A message can be activated from the tone activation inputs on TB1. For example, a dry contact,
either normally open or normally closed (depending on the configuration) will activate a tone when
it is connected between the associated message (TB1-1 through TB1-6) and COM (TB1-7). The
configuration of these channels is described in "Input Configuration" on page 7. These inputs are opto-
coupled to reduce the possibility of noise on the signal lines falsely activating a message.
There are two sets of contacts that can be used to monitor the status of a CommCenter. When power is
applied, a relay with form C contacts is activated. These contacts are connected to TB2 and are labeled
Power Monitor Relay. The second set of contacts monitor activation of any of the six messages or a
cascaded input. These contacts are labeled Push-to-Talk (PTT) Relay on TB1.
Power Requirements
The Model 300MB can be operated on 120 Vac, 240 Vac, or 24 Vdc input power. To prevent power to
the CommCenter from being accidently turned off, the unit does not have a power switch.
8
Table 2 Model 300MB Series D motherboard
MESSAGE
JUMPER
PRIORITY
J9
TONE1
PRIORITY
J10
TONE 2
PRIORITY
J11
TONE 3
PRIORITY
J5
TONE 4
PRIORITY
J4
TONE 5
PRIORITY
J3
TONE 6
NO NC configures an individual channel to inter-
face to normally open (NO) or normally closed
(NC) contacts.
NOTES:
R M configures an individual channel to inter-
face to a latched contact (R) or a momentary
contact (M).
SHOCK HAZARD — Do not perform any installation or maintenance on this
system when power is on. Because the 300MB does not have a power switch,
ensure that the power is disconnected before proceeding. Failure to heed
this warning may cause serious injury or death.
Model 300MB-SD CommCenter Series D1
MARKING
JUMPER
NO NC
J12
NO NC
J14
NO NC
J13
NO NC
J8
NO NC
J7
NO NC
J6
MARKING
R M
R M
R M
R M
R M
R M