Zeta Alarm Systems.
ZNDC Installation and Operation Manual
Revision 1.0
Part # MAN-ZNDC-01
Page 18
5. Operation
5.1 “Comm Test” Switch
The “Comm Test” switch provides a way to manually test the operation of the ZNDC. When the
switch is pressed, the unit will attempt to send a “Manual Test Report” event to the central station
(event code 601). Test reports (whether manual or periodic) are sent on alternating phone lines.
That is, if one test report is sent via line #1, the next will be sent via line #2.
5.2 Ademco Contact ID Protocol Notes
5.2.1. Handshake
The Contact ID protocol expects a dual-tone handshake (1400Hz for 100ms, 0Hz for 100ms, and
2300Hz for 100ms). If the ZNDC does not receive a handshake within 8 seconds after the last digit
of the phone number has been dialed, it will hang up and swap lines.
5.2.2 Event Format
An event is sent using DTMF tones (100ms per digit: 50ms on, 50ms off) in the following format:
ACCT MT QXYZ GG CCC S
ACCT = 4 digit account number
MT =
message
type
(always
“18”)
Q =
event
qualifier
(“1” = new event, “3” = restoral, “6” = previous event)
XYZ =
event
code
GG
= group number (Classic 2000 Mk II uses this for the “loop number”)
CCC = zone or sensor number (Classic 2000 Mk II uses this as the device address within the
loop specified in the “group” field)
S
= checksum ((sum of all message S) MOD 15 = 0)
5.2.3 Kissoff Tone
The ZNDC expects a kissoff tone of 1400Hz, lasting at least 400ms, followed by 250ms of silence.
If the ZNDC doesn’t detect the kissoff tone, it will resend the event. Events will continue to be sent
(event message plus kissoff) until the ZNDC has sent all the events in its queue.
5.3 Phone Line Usage
The ZNDC always attempts to call out on line #1 first. If line #1 has a fault or is disabled, line #2
will be selected. If both lines contain a fault, the ZNDC will alternate between lines. If the ZNDC
dials out on a line and does not detect a handshake, it will try again. If the ZNDC sends an event
message and is unable to detect a kissoff tone in four attempts, it will try again. When a certain
number of consecutive failures occur, the ZNDC will switch lines. It will continue attempting to
report the event(s) until it is successful.
5.4 Phone Line Supervision
When not reporting a message, the ZNDC continuously supervises the phone lines. It toggles
between lines approximately every 30 seconds. Thus, a phone line fault (or fault restoral) may take
up to a minute or so before it is recognized.
