PRELIMINARY:
Model SK-FFT Manual — P/N 54711:B2 12/18/2020
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Section 5: Audio Phone Circuit Installation
5.1 List of Devices
5.2 Maximum Number of Devices
The SK-FFT supports up to 48 zones. Each zone consists of one addressable monitor module (SK-MINIMON) and a minimum of one Fire
Fighter Telephone Jack (FFT-FPJ).
5.3 Wiring Requirements for the Audio Telephone Circuit
The following information applies to the FFT-FPJ Fire Fighter Phone Jack.
5.3.1 Single Phone Jack Audio Circuit in Class B Configuration
No special wire is required for the Audio Telephone Circuit. The wire can be untwisted, unshielded, twisted or shielded as long as it meets
the National Electric code 760-51 requirements for power limited fire protective signaling cables.
54 Ohm maximum impedance - 12 to 18 AWG.
Twisted, shielded wire is recommended for maximum protection against EMI and AFI emissions and susceptibility.
If using shielded cable, attach the shield to Grounding Stud below TB6 of the FFT.
Figure 5.1 illustrates single phone jack configuration wiring the audio circuit and SLC for Class B Configuration. Audio circuits must be
connected to FFT phone out terminals for all Class B audio configurations
.
Figure 5.1 Single Phone Jack Audio Circuit Wired in Class B
Figure 5.2 EOL Example
Part Number
Description
FFT-FPJ
Fire Fighters Telephone Jack
Table 5.1 Devices
NOTE:
Do not ground shield on both ends.
Contact EOL Connected
(see Figure 5.2 for EOL
example)
Caution!
For System Supervision-For Terminals 2 and 3, do
not use looped wire under the terminals. Break wire
run to provide supervision of communications.
4.7K W, 1/2 watt ELR (Install on
the last device for Class B
telephone circuit only).
