RS232 Control
Introduction
This document describes the remote control protocol for controlling the MZ8/12 via the RS232 interface.
The document relates to MZ RS232 control protocol version 1.0. Any updates to this protocol will be posted on the Arcam Extranet website at http://www.arcam.co.uk/extranet.
Serial Cable Specification
1 6 
FemaleDB9 
9 
5
The cable is wired as a null modem:
Connector 1 pin | Connector 2 pin | Function |
2 | 3 | Rx Tx |
3 | 2 | Tx Rx |
5 | 5 | RS232 Ground |
Data transfer format
•Transfer rate: 38,400bps.
•1 start bit, 8 data bits, 1 stop bit, no parity, no flow control.
Conventions
5
9 
DB9Female 
6 1
All hexadecimal numbers begin 0x.
Any character in single quotes gives the ASCII equivalent of a hex value. <n> represents an unknown or variable number.
Command and response formats
Communication between the remote controller (RC) and the MZ8/MZ12 takes the form of sequences of bytes, with all commands and responses having the same basic format. The MZ8/MZ12 shall always respond to a received command, but may also send messages at other times.
Each transmission by the RC is the following format: <St> <Zn> <Cc> <Dl> <Data> <Et>
St (Start transmission): 0x21 ‘!’
Zn (Zone number): see below.
Cc (Command code): the code for the command
Dl (Data length): the number of data items following this item, excluding the ETR
Data: the parameters for the command
Et (End transmission): 0x0D
Each response by the MZ8/MZ12 is the following format: <St> <Zn> <Cc> <Ac> <Dl> <Data> <Et>
St (Start transmission): 0x21 ‘!’
Zn (Zone number): see below.
Cc (Command code): the code for the command
Ac (Answer code): see below.
Dl (Data Length): the number of data items following this item, excluding the ETR
Data: the parameters for the response of length n. n is limited to 255.
Et (End transmission): 0x0D
The MZ8/MZ12 responds to each command from the RC within three seconds. The RC may send further commands before a previous command response has been received.
13