Service manual

12
Functional Description
DCB, DCFCB and DCFCTB Models
Functional Description
System Operating Description
Siren Activation
The DTMF versions of DCFCTBs enable the user to program an ARM string into the
controller for extra security. If an arm string is not programmed, then an ARM
command is not required to activate a function. Digital versions of DCFCTBs do not
use the ARM function.
Activation Using the ARM function
To start a siren activation via the radio, it is necessary to ARM the siren before
initiating a siren function; such as, a Wail or Steady. Once the siren is ARMed, it
remains ARMed for 255 seconds or 4.25 minutes. Upon activation of the siren, it runs
until the function times out, is canceled, or is reset. If the siren function is greater
than 4.25 minutes, you must send another ARM command prior to sending a
CANCEL command to shut off the siren. The ARM command is not required prior to
sending a RESET command.
To start a function by either land line or pushbutton it is necessary to provide a one
second closure on the landline or a one second depression of the pushbuttons.
Site Status Monitoring (DTMF only)
The siren controller will report when polled from the SS2000 or when one of its
sensors changes state. The status of the site is encoded in a 9-digit DTMF string that
is designed to work with a Federal Signal SS2000 to decode, format, and time and
date stamp the received string. For detailed information about the DTMF coding
format, refer to the Software Description of DCFCTB Encoding Format section on
page 36.
Automatic Reports
The DCFCTB automatically sends back a report if one of the following sensors has a
change of state: AC, Low Battery, Intrusion, or the siren is activated locally. The
control station can also be set to automatically poll the system at a predefined
interval. Automatic reporting may be optionally disabled on DCFCTBD systems. The
DCFCTB is equipped with a carrier detect transmit hold off that causes the unit to
wait until the channel is clear before an Automatic report is transmitted.
Growl Test
The Standard Growl Test runs the rotator for 12 seconds and the chopper motor until
the sensors latch or a maximum of 2 seconds. This function is commonly used when
doing periodic testing to verify proper operation while generating minimal sound.