Lyngdorf CD-2 - Introduction to Lyngdorf CD-2 External Control; Serial Port Settings; Commands and Requests Format

2 Model CD-2 – External Control Manual
Introduction
The purpose of this document is to describe how the external control interface of the device
works.
Serial Settings
The serial port settings are always 8 data bits, no parity and one stop bit with a baud rate of
115200.
Commands and Requests
All commands and requests start with the ‘!’ character.
Commands end with a combination of the Carriage Return character (ascii 0x0D, referred to
as <CR> in this document) and Line Feed (ascii 0x0A, <LF>). Often, a single <CR> is used,
but because different systems handle these characters differently, it is also allowed to end
with <LF>, <CR><LF> or even <LF><CR>. In this document, it is expected to be <CR><LF>,
but all of these combinations are allowed instead.
Requests end with the character ‘?’ and <CR><LF> (or any <CR><LF> combination as
above).
Commands can have parameters, these are enclosed in parenthesis.
Replies to a request are formatted as the request with the reply values as parameters.
Replies always use the <CR><LF> combination of line-end characters.
Commands and requests are not case sensitive. In addition, it is possible to subscribe to
status changes from the device. In this situation, whenever a status has changed (new state,
new track etc.) the device will send a status. This status is formed exactly like a reply to a
request, except it is followed by the character '!' before the <CR><LF> to indicate, that this is
an asynchronous message, not a reply.
!COMMAND<CR><LF>
Command
!COMMAND(param)<CR><LF>
Command with parameter
!REQUEST?<CR><LF>
Request
!REQUEST(reply)<CR><LF>
Reply to a request
!REQUEST(status)!<CR><LF>
A status, which has changed
Commands and requests which are malformed or has invalid parameters will just be ignored.
If a command or request is correct but followed by garbage before the line end chracter(s),
the command or request will be executed and the garbage ignored.