User`s guide

7-8
In GPRS mode, unlike Internet servers that have fixed (static) Internet addresses, some
mobile devices are assigned temporary (dynamic) addresses that go away after the
connection is terminated. Therefore it is not possible to contact the DCM-200 over the
Internet. Yet there may be times when it is desirable to communicate immediately with
the DCM-200 or ANSI meter rather than wait for it to call in. To overcome these
limitations the DCM-200 supports the ability to be “paged”. When paged, the DCM-200
will immediately call back to the central computer.
Many cellular accounts are (or can be) assigned a “voice” phone number. If the DCM-
200 is configured to answer incoming phone calls it is possible to use this as a paging
number, which will then trigger the DCM-200 to immediately call back. The is enabled
by checking the “Respond to Voice Calls” box in MP32 (see Chapter-5).
In CSD mode the unit will answer the call and will attempt to communicate with the
remote modem if there is one. The call will be terminated if 30 seconds pass without a
successful modem exchange or if the other end hangs up. This will trigger the unit to
call back to the primary phone number.
In GPRS mode the unit will answer the call and will immediately hang up. It will then
originate a GPRS connection to the primary IP address and port number.
See Chapter-4 about having the phone number programmed into the SIM card.
7.9 Paging via SMS Message
SMS (Short Message Service) is a feature that is often included with a cellular account,
or can be added at a minimal charge. SMS allows short text messages (email) to be
sent to a cell phone. SMS can be used to page the DCM-200 if the unit has been
configured to respond to SMS messages. The actual content of the message is
unimportant and is erased as soon as it is received. When an SMS message is
received, the DCM-200 will call in to the primary phone number or IP address.
The cellular service provider will give you instructions on how to send a text message to
the mobile device. Often the SMS address includes the voice phone number, such as
[e-mail]
or something similar. See Chapter-4 about
having the phone number programmed into the SIM card.
Make sure there is at least one character in the message because some providers will
not forward an empty message. Also note that a message may not necessarily arrive
immediately after it is sent. If the network is congested the message may not arrive for
minutes after it is sent.
7.10 Emergency Call In During a Power Outage
If the DCM-200 is powered from the AC lines and contains a backup lithium battery, the
unit will be able to call in to report the power failure. The unit must be configured to
originate calls for this to work. When the unit calls in, it will report an “AC-OFF” alarm to
the DC-2000 data collection system. See Chapter-6 about processing hardware alarms.