Crestron
e-control Mail SW-MAIL
50
••
Control Messages
Installation & Reference Guide — Doc. 5798
Identification
For the server to recognize control messages, the
Process control messages
option
must be checked in the
e-Mailbox Signal Block Definition
window
.
Otherwise, none
of the following applies, and messages which might have been interpreted as control
messages are instead interpreted as normal messages.
N
OTE
:
e-Mailbox signal blocks must either have an IN box (
i.e.,
a scroller bound to the signal block
to act as an IN box), or have the
Process control messages
option checked. If neither of these options
are selected, there is nowhere for the mail to go. This is an error condition and if it exists, the server
protocol will not start. ¶If there is an IN box but
Process control messages
is not checked, all
messages are downloaded to the IN box. ¶If there is no IN box and
Process control messages
is
checked, only control messages are considered. Other messages are ignored (and possibly deleted if
the
Delete messages as downloaded
option is checked — which is strongly recommended to avoid
having to download the headers of all such messages every time mail is checked).
Spaces and case are ignored. For
example, a control message could
have a subject header starting
with
ctrl >
[with a space
before the angle bracket].
Secondly, for the server to recognize a control message as such, it must conform to
the definition of a control message which is any message with the string
CTRL>
at
the start of the subject header. Once the server decides that a message is a control
message, the message must conform to certain syntax rules. Otherwise, error
messages appear in the server log.
Message types
There are two basic types of control message:
•
A single-signal control message where the signal is in the subject line itself. In
this case, the server never downloads the body text from the e-mail host,
which is clearly a more efficient way to go when there is only one signal to
transmit to the control system.
•
A multi-signal control message where the subject line contains the simple
command
SCRIPT
. When the server encounters such a message, the body
text is downloaded and any signals found therein are transmitted to the control
system.
Syntax
Whether a single control signal appears in the subject line, or multiple signals are
dispersed throughout the body text, the syntax is the same.
There is one signal per line. All such lines begin with
CTRL>
followed by a signal
equate, as follows:
CTRL>
type number
=
value
where:
type
is
A
,
D
, or
S
, for analog, digital, or serial, respectively.
number
is the number,
n
, in the
SignalA
n
, SignalD
n
,
or
SignalS
n
signal.
value
is arbitrary, subject to the syntax for the signal type.
The syntax for signal values is as follows:
Analog
An unsigned 16-bit value represented either as:
A decimal (base 10) integer, in the range is 0 to 65,535.
An hexadecimal (base 16) integer, in the range $0000 to
