RS232 Serial Interface Specification

This document describes the requirements for communicating with the Detection Systems DS7400XI

control panel through the Detection Systems DS7412 Serial Interface module. The purpose is to allow

control of the panel through a serial interface for applications such as home automation..

TRANSMISSION REQUIREMENTS

The serial interface device shall be a standard RS-232 compatible device. The maximum baud rate that can be used to communicate with the panel is 9600 baud. It has been found that 2400 baud produces no faster results because of the necessary time delay at the panel, therefore 2400 baud is recommended as it should be a more reliable speed.

The panel or serial interface device shall repeat a transmission up to three times if a REPEAT command is received or a time-out occurs.

Each byte will be formatted as:

One start bit

Eight data bits, least significant first.

One odd parity bit

One stop bit

Each transmission is limited to 64 bytes including the command and column parity bytes. The transmission may be as short as two bytes (command and column parity). Each transmission shall contain only one command.

The general form of all transmissions is:

Wait 200ms from end of last transmission

One command byte (see commands section)

Data bytes (length implied by the command type, zero through 62 data bytes)

One odd column parity byte (with it's own parity bit)

The panel is always a slave, it does not send commands unless it is responding to a command sent by the serial interface device. (except speed sync 77s and a LOGOUT command after a time-out.)

INITIAL CONNECTION REQUIREMENTS

A ds7400XI must have a DS7412 attached. The DS7412 converts the serial data from the Serial Interface

Device to Option bus data that the panel can understand. The DS7400XI control panel must be

programmed to enable the DS7412, send no events to the printer, the baud rate must match the serial

interface device baud rate (default 2400), odd parity, hardware flow control, 1 stop bit, and 8 data bits. To

set this information in the DS7400XI panel version 3.0 or greater, the following addresses should be programmed as noted.

Address 0419 must be programmed as 1 0

Address 0420 must be programmed as 2 5

85 - SEND EVENT, Send the highest priority event. 85 (XX) SS Where XX is the partition number for partitioned

panels. If XX = 00 then send the highest priority event for the entire panel. If there are no events to be sent send a NAK.

Only the highest priority event for the partition or panel is available. Lower priority events occurring before this one has been requested will be lost. The panel's response is as follows:

byte 1 = 85H

byte 2 = 1 = fire alarm

= 2 = keypad fire

= 3 = keypad emergency

= 4 = keypad medical

= 5 = duress code used

= 6 = unauthorized entry

= 7 = burglar point alarm

= 8 = supervisory

= 9 = fire trouble

= A = fire point trouble

= B = burglar point trouble

= C = cancel alarm

= D= open

= E = close

= F = forced bypass

= 10 = bypass

= 11 = point restoral

= 12 = fail to close

= 13 = fail to open

= 14 = history buffer dump

= 15 = test messagebyte 3 = for closing bits 0 - 2 = arming level (otherwise 0), bits 3 - 7 = 0.

= 16 = zone trouble restore

byte 3= user ID for open, close, duress, unauthorized entry, and cancel alarm (FE = auto arm, FF = remote arm/disarm, 0 = keyswitch). For all other types this is the point number.

byte 4 = column parity