EQUIPMENT:  T1200-C 
PUBLICATION:  MARINEC-P-A 
  ISSUE No. & DATE:   3  02/14 
© 2014 Thorn Security Ltd      PAGE 51 of 67 
Registered Company: Thorn Security Ltd.  Registered Office: Dunhams Lane  Letchworth Garden City  Hertfordshire  SG6 1BE 
19.4  Auxiliary Supply 
An auxiliary supply  output  is available to power 
external field equipment from the panel. This 
voltage is nominally  27.3Vdc  but varies during 
mains-failed conditions. See section 21.  below for 
details of maximum load. 
The output is fused using an electronic device, and 
fuse activation will be indicated as Fuse Failed on 
the panel display. The fuse can be reset after 
removal of the fault by operating the Reset button 
on the display. 
The auxiliary supply terminals are labelled Aux DC 
0V and 24V. Although two sets of terminals are 
provided, they are both protected by the same fuse 
circuit and therefore the total load across both sets 
of terminals must not exceed the rated value. 
Note: If equipment draws current from the 
auxiliary supply during the mains-failed 
condition this must be included in the battery 
capacity calculations. 
19.5  Fire Protection, Fire Output and 
Fault Output Signal Outputs 
These outputs are factory set to the fault-monitored, 
powered mode of operation but can be configured 
at site to volt-free relay outputs [See 17.23 above]. 
Connection details for both types of configuration 
are provided in Figure 24. 
19.6  Use of Auxiliary Inputs 
Auxiliary inputs are provided to allow remote 
operation of the following functions: 
Auxiliary Input:  Type of activating switch: 
Remote Manual Fire 
Alarm/Muster. 
Two-position latching 
 
To activate an input, 0Vdc should be connected to 
the input circuit via a normally open contact 
arranged to close. [See Figure 22 – Auxiliary I/P 
connection detail] 
 
Figure 22 – Auxiliary I/P connection detail 
Sil, Evac, Reset 
or Class Change
Aux 0VDC
External normally open 
switch or relay contact, 
closing to activate I/P
Field WiringPanel Wiring
 
Note: “Evacuate” or “Evac” = Manual Fire 
Alarm/Muster 
 
Note: To prevent unauthorised operation of the 
system, any manually operated auxiliary 
input must be operated by a key-switch. 
The key to the switch should be held with 
the panel’s access control key. 
 
19.7  Sounder Circuits 
The T1204 panel has 4 sounder circuits, each rated 
at 0.5A. The T1216-C and T1232-C panels have 4 
sounder circuits each rated at 1A. The circuits are 
reverse polarity monitored for open and short circuit 
faults. All connected field devices must be polarised 
to allow correct fault monitoring. To prevent 
damage to the control panel, any solenoid devices 
such as bells must also have a suppression diode 
fitted as shown in Figure  23  –  Alarm circuit 
configuration. 
The circuit must be terminated with a 3K9 end-of-
line resistor. 
 
Figure 23 – Alarm circuit configuration 
Polarising 
diode 
[1
N4002S
]
Suppression 
diode 
[1
N4002S
]
Bell
Electronic 
sounder
3K9 
End of 
line 
resistor
Alarm +
Alarm -
 
The voltage drop on each alarm circuit should be 
calculated to ensure that the minimum voltage at 
the end of each circuit exceeds the minimum 
required by each sounding device. 
The voltage at the end of the circuit is given by: 
V
Amin
 = V
Omin
- (I
A
 x 2 x L x R
C
) 
V
Amin
 = Minimum Alarm Voltage 
V
Omin
 = Minimum Output Voltage** 
I
A
 = Alarm Current in Amps 
L = Alarm Circuit Length in metres 
R
C
 = Cable resistance (Ohms per metre) 
** Min O/P voltages: 
T1204 = 19.2V 
T1216-C = 19.2V 
T1232-C = 18.4V 
The resistance per metre is as follows: 
1.5mm
2
- 0.015Ω per metre per core 
2.5mm
2
- 0.009Ω per metre per core