The External_Control Protocol; Controlling Axcess From The Outside; Sending Commands - AMX AXCESS CONTROL SYSTEM PROGRAM Instruction Manual

The External_Control Protocol

Controlling Axcess from the Outside

Not every Axcess system is controlled by control panels; sometimes the control comes from
another device, such as a computer (via modem, if necessary) or another Axcess system. To
facilitate this, Axcess supports a simple serial communications protocol that allows every Axcess
function to be controlled from an outside source via an AXC-232 RS-232/422 Control Card or RS-
232 port on another Axcess control system.

Sending Commands

To control Axcess from a remote machine, you must first use the EXTERNAL_CONTROL
keyword in the DEFINE_START section of your program to tell Axcess which device the RS-232
card is. For example:
DEFINE_START
EXTERNAL_CONTROL (RS232)
The device RS232 will now be used as an external control port. EXTERNAL_CONTROL can only
be used once in the DEFINE_START section of your program.
Next, you must send command packets to Axcess. The table below lists the command packets. Each
of these packets consists of the following:
!
!
!
!
Command packets
Command
TURN CHANNEL ON
TURN CHANNEL OFF
GET CHANNEL STATUS
SEND STRING
SEND COMMAND
DO PUSH
DO RELEASE
DEVICE ID
READ ADDRESS
PULSE
RESPONSE MASK
LOAD STRING
Axcess Programming Language
An attention character-prepares Axcess for the transmission; it is always $2A (*) for
sending commands, and it is always $26 (&) for responses.
A command number.
One or more parameters.
A checksum byte-the sum of all of the characters in the packet (except itself), modulo
256. Its purpose is to make sure that the packet was not garbled during the transmission.
Packet structure
'*' <1> <DEVICE> <CHANNEL> <CHECKSUM>
'*' <2> <DEVICE> <CHANNEL> <CHECKSUM>
'*' <3> <DEVICE> <CHANNEL> <CHECKSUM>
'*' <4> <DEVICE> <# OF BYTES> <STRING> <CHECKSUM>
'*' <5> <DEVICE> <# OF BYTES> <STRING> <CHECKSUM>
'*' <6> <DEVICE> <CHANNEL> <CHECKSUM>
'*' <7> <DEVICE> <CHANNEL> <CHECKSUM>
'*' <8> <DEVICE> <CHECKSUM>
'*' <9> <DEVICE> <ADDRESS> <CHECKSUM>
'*' <1Ø> <DEVICE> <CHANNEL> <CHECKSUM>
'*' <11> <MASK> <CHECKSUM>
'*' <12> <DEVICE> <# OF BYTES> <STRING> <CHECKSUM>
The External_Control Protocol
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