Bell System 719S, Installation & Operation Manual

Page: 10 / 20

719S 2 Door Switching Unit
PD-008 Iss 6 Installation & Operation Manual Page 10 of 20
Speech not audible when
phone is buzzed.

No/low supply to Speech Unit. Check 11.5V-
15V across 'C' and 'H' on the unit.

Faulty 'R', 'O', or 'T' line between Switching
Unit and phone or Switching Unit and panel.
Telephone will not buzz
(no green LED illuminated
on the 719S)

Faulty 'O' or 'I' line between Switching Unit
and phone.

‘B’ terminal on the 719S not wired to the call
button commons in the entrance panel (only
if no ringing on several phones). Check for
12V on the ‘B’ wire when the TEST button
has been pressed (green LED on).

‘B’ terminal connected to 12V instead of only
to call buttons on the other entrance (green
LED stuck on for other Door). Check by
taking out the B terminal for the other Door
and waiting for the green LED to go off after
the speech time.

AC telephone systems only: Faulty
>
H
=
or
>
O
=
line between switching unit and panel. As a
check, short
>
H
=
to
=
O
=
at the switching unit
and try again.

Faulty
>
V
=
connection to phone. Check 10-
15V between
>
O
=
and
>
V
=
at the phone (BS-LX
phone ONLY).

Faulty panel button.

No/low supply to Switching Unit - Check
11.5V-15V on Switching Unit supply input.

Power supply has been wired to wrong
Switching Unit input. Check an AC supply
has been wired to a 12V AC input or a DC
supply wired to a 12V DC input, where
installed.
Lock button does not
operate release.

AC telephone systems only: Fault on
>
H
=
or
>
O
=
between switching unit and panel. As a
check, short
>
H
=
to
>
O
=
at the switching unit
and try the lock button again, when active.

Fault on 'Z' or 'O' line. Check shorting 'Z' to
'O' at the Switching Unit, when active (green
LED on), operates the release.

Lock release supply low. Check 11.5V-15V
across the release with the lock button
pressed and the phone active.

Using a fail-safe output but no DC power
supply present.
Tradesman/Exit button
inoperative.

Time Clock is not running or incorrectly set
(Tradesman button only).

Check connections to 'EXIT' input.
Lock release operates all

If the lock is a 'fail safe' type it has been