rev1 ā Dec 2013 www.digitalcomtech.com 24
Access Point Name (APN) for GPRS set up
A GPRS session enables the unit to communicate with IP networks (IP addresses).
Although the most common IP network is the Internet, by specifying an APN the cellular
carrier can enable your unit(s) to work on a user-private IP network that does not
necessarily communicate with the Internet. When using a private APN, devices like
the Syrus, Cellular Phones, PDAs, PCs, Servers, etc can only be accessed by devices on
the same APN. There are several reasons why a cellular carrier may use different APNs,
but the important thing is that an APN is needed for the unit to start a GPRS session, for it
to be able to send and receive data over IP networks.
The most common situation is an APN with Internet access. Any device using this APN
has the ability to communicate with any IP network on the Internet. Specifically if you are
running your AVL (Automated Vehicle Location) server on the Internet, this is the kind
of APN you want.
An APN has the form of a server name on a dot-separated format and it is supplied by the
cellular carrier. For example:
this.is.an.apn.com
or
internet.carrier-name.com
Setting the APN on the Syrus is also done with the RF message. An "empty" APN may be
configured too. An empty value is used when a GPRS session is not desired (GSM
communications only, Voice and/or SMS). This message is used as follows:
To set the APN to internet.carrier-name.com send to the unit:
>SRFAinternet.carrier-name.com<
To leave the APN parameter empty:
>SRFA<
The GPRS registration status can be consulted with the XANS message and/or with the
NET (green) LED.
An APN configuration can be issued at any time and the unit will start registering to the
GPRS network as soon as the GSM registration process is done and the APN parameter is
set.
The Syrus will not start a GPRS session if it is not registered on the GSM network. And
when the GSM network is lost the GPRS session is lost too. However the unit may work
on the GSM network regardless of the GPRS session state.
The GPRS registration process is usually charged by the cellular carrier, having an
incorrect APN will make the unit constantly try on failing GPRS sessions which could
lead to an excess on the unit's bytes consumption.
Warning: The APN may be changed over the air which will cause the Syrus to loose
communications with the server.
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