EZ-Key Keypad with integrated audio
Technical Manual
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confidential and is not to be used for any purpose or disclosed to a third party without the express and written consent of
Keymat Technology Ltd., Copyright 2015. All rights reserved.
EZ-Key + Audio - Technical Manual Rev 1 Apr 2015
www.storm-interface.com
Page 19 of 35
API for controlling the Keypad from the Host Computer
This section provides details on how the EZkey can be controlled from a host that has USB capabilities.
The API incorporating this command set is downloadable separately from
www.storm-interface.com.
Device Communications and Message Format
EZKEY_VOIP
keypad
uses the ASCII/binary Message format described below. Every message that is sent from a
host should be acknowledged with the control byte ACK (0x06). A retransmission should be initiated if an NAK
(0x15) is received or if no acknowledge is received at all.
Message Formats
A Alpha character, 'A'-'Z' and 'a' - 'z'
C Control character one byte in length.
H Hexadecimal
characters, ‘0’-‘9’, ‘A’-‘F’
N Numeric character, ‘0’-‘9’
S Special characters, entire character set 0x00 - 0xFF
ASCII Message Format
Message
Field
Type
Length
Description
1
STX
C
1
Control
character
Start
of
Text
=
0x02
2
Message
Id
H
2
Defines
the
type
of
message
and
format
of
the
data
field
3
Data
Length
H
2
Hexadecimal
value
represented
in
ASCII
defines
the
number
of
bytes
in
the
data
field.
'00'
to
'FF'.
Maximum
data
field
size
is
256
bytes.
4
Data
Field
S
var
In
binary
format
5
ETX
C
1
Control
character
ETX
=
0x03
6
LRC
C
1
Longitudinal
Redundancy
Check
Digit,
calculated
on
all
previous
data
including
STX
