Installation manual

D9124 Operation & Installation Manual
Page 40
© 1996 Radionics
74-06799-000-D 2/96
The D928 uses the primary phone line to dial a primary, backup, or duplicate phone
number. The D9124 switches to the secondary line only when the D9124 senses trouble
on the primary telephone line. During primary telephone line failure, the D9124 transmits
all messages on the secondary line.
When the primary telephone line trouble clears, the D9124 sends the restoral message to
the receiver on the primary telephone line. All messages are again sent on the primary
line.
Watchdog Feature
The Watchdog circuit monitors the panel's CPU (Central Processing Unit) for proper
operation. If the CPU fails, the buzzers on the D9112LTB and the D928 sound. The
buzzers stops sounding when the CPU begins operating normally.
D928 Status LEDs
Four LEDs mounted on the front edge of the D928 module indicate primary phone line
failure, secondary phone line failure, failure to communicate, and AC power status. When
programmed and operating normally, only the green AC power status LED should be
illuminated. See Figure 19.
AC POWER
LED
(GREEN)
PRIMARY
FAIL LED
(YELLOW)
SECONDARY
FAIL LED
(YELLOW)
COMMUNICATIONS
FAILURE LED
(YELLOW)
BLK - T O
TERMINAL 10
GREEN - TO
TERMINAL 1
BUZZER
CONNECT TO FLAT
RIBBON CABLE
PHONE JACK TO PRIMARY
PHONE LINE - RJ31X
PHONE JACK TO SECONDARY
PHONE LINE - RJ31X
PHONE JACK TO
TELCO CONNECTOR
ON D9112LTB
J1
J2
J3
Figure 19: D928 Dual Phone Line Switcher Module