Bell
Technical Support
System
Tel 0845 121 4008
(Telephones) Ltd
Fax 0845 121 4009
Web
www.bellsystem.co.uk
Troubleshooting Guide
Audio Door Entry Systems (single entrance)
(9nn, VRKn or BLn series)
Most systems use the 801 phone, 801P on systems above 20 flats.
Twisted-pair cable must be used (CW1308 telephone or Cat5e data cable). Alarm
cable is not recommended and can cause problems with speech.
Phone connections
Terminal
Meaning
I
Call / call button (12V to ring)
R
Microphone
O
Common for ring, speech and lock button (0V)
T
Speaker
Z
Lock button (Z shorts to O when the lock button is pressed)
V
12V DC Phone supply (BS-LX and 500X series only)
L
Door Monitor (connecting L to 0V brings green LED on, BS-LX and
500L series only)
51 Speech unit – 12V AC or DC operation
61 Speech unit – 12V AC or DC operation
801 Series phone with Electronic ring – 12V AC or DC operation
801 Series phone with Mechanical buzzer – 12V AC only
500A, PA – 12V AC only, other 500 series 12V DC only
If a phone has 500 PAD on it check which letters are crossed out. If the A is crossed
out the model is a 500PD.
BS-LX phone – 12V DC only
Common Faults
A very high percentage of calls to our technical support number, regarding new
installations, are resolved to faulty wiring. The reasons for these are various: -
•
Broken cores, especially short links, sometimes broken inside the insulation.
•
Connectors clamped onto the insulation instead of copper.
•
Short or open circuits due to cables having been stapled or nailed through.
