User`s guide
5-7
required for g18-based units. g20-based units are capable of determining the
appropriate frequency.
5.4.16 GPRS Access Point Name
If the DCM-200 will be making an Internet connection (GPRS mode), the cellular service
provider will need to provide an Internet APN (access point name). In order to connect
to the Internet, the provider has its own computer equipment called a “gateway” server.
The server will usually have an APN in the form of a domain name, such as
“myserviceprovider.com”. Contact your service provider for this information.
Service providers may have several different gateways to choose from, depending upon
the type of service required. “Web phones” (cellular phones that support Internet
access) are generally assigned to a gateway that only connects to WAP services
(wireless application protocol). The DCM-200 requires full Internet access because
the data collection software could be running on any server located anywhere in
the world. Full access gateways are usually assigned to customers who will be
connecting a wireless modem to a personal computer.
5.4.17 GPRS Connection Command
This command is issued to the cellular modem to request a GPRS (Internet) connection.
For most cellular service providers the phrase “ATD*99#” will work, and this is the
default setting for the DCM-200. If you are having problems connecting, this could be
the problem. Contact your service provider for more information
.
5.4.18 Destination Modem Baud Rate
This is used for CSD mode only. It defines the baud rate of the modem equipment at the
data collection computer site. Selections are Auto, 300, 1200, 2400, 4800, 9600 and
19.2k bits per second (bps). The ‘AUTO’ setting can be used if the cellular service
provider supports automatic baud rate detection. In Metretek’s experience most
providers do not support automatic baud detection, so it is best to specify a specific baud
rate. Most cellular providers do not support bit rates less than 9600 bps, and the DCM-
200 does not support rates lower than 4800 bps. If a Metretek MODSMOD modem
array is being used, a 9600 bps MODSMOD card will be required.