APPENDIX D
— SMS INTERFACE
The Vanguard 3000 has the capability to receive and send SMS messages. This appendix describes how this feature is
implemented and can be used as a technical reference by system administrators and developers installing and using
Vanguard 3000. The standard on which the Vanguard 3000 SMS interface is based is the NMEA (National Marine
Electronics Association) 0183 Standard for Interfacing Marine Electronic Devices version 2.30 (March 1, 1998).
Note:
The current SMS implementation only supports 7-bit dada consisting of a subset of the standard ASCII character
set (160 characters, max.). Future versions may add raw binary 8-bit data (which also may limit message length to 140
characters max.).
SMS MESSAGE ROUTING
The Vanguard 3000 may have more than one SMS client internally. Unlike IP, SMS messages are not easily routable.
(Although SMS does have a UDH [user-data header], the Vanguard 3000 does not make use of this since it makes the
sending of messages significantly more complex.)
SMS Message Prefix, Outgoing
Outgoing SMS messages are directed according to the phone number supplied by the client. The SMS Manager places
no restrictions on the contents of the outgoing message body, although a prefix scheme similar to the one used for
incoming messages could be implemented if the Host application needs to receive SMS messages from multiple
applications.
SMS Message Prefix, Incoming
CalAmp’s SMS Manager makes use of message prefixes to route incoming messages to client applications. Each client
registers a unique prefix string. The SMS Manager inspects all incoming messages to these prefixes and routes the
message to the appropriate client.
For example, if the client registers “MY_CLIENT” and the host wishes to send a command “GETSTATUS,” it must be sent
as follows:
MY_CLIENTGETSTATUS
Note that the client will receive the complete message including the prefix.
If a client attempts to register a prefix that is already registered by another client, the request will be refused and an
error message will be returned.
Note that a client may at any time re-register using another unique prefix string. In order to unregister, a client must
disconnect from the SMS server.
Blank Prefix
A client may register a blank string as the prefix. The client will receive all messages with prefixes not matching any of
the other registered client prefix strings. Note that as with a nonblank prefix, only one client may register a blank
prefix.
Vanguard 3000 Series Multicarrier Cellular Data Modem & IP Router PN 001-7300-100 Rev. B
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