Modem communication channels permit the user to use the phone system's world wide network to obtain necessary information from the flow computer. The necessary building blocks are the flow computer, the remote modem, the local modem, the host PC loaded with the appropriate software.
In most applications the host system will call into the remote meter. The ST1 equipped with a compatible modem will be configured to answer the incoming call. Once the connection is established the host computer can then ask for information using the KEP protocol. KEP's ST1 flow computer will respond with the requested information.
In more advanced applications the ST1 Flow computer can "call in" to the host system at a specified time. The host system client application would then take control of the information exchange session. This alternate technique can also be used when it is desired to have the flow computer call in upon detection of a sensor or flow computer malfunction. The STI settings include the phone number you wish to call, the number of retries if the phone number is busy, and the conditions upon which to initiate a call. The ST1
can also handle the special actions such as hang up if the phone connection is lost or if there is no activity for several minutes.
KEP offers a compatible port powered modem which is recommended for remote metering. The MPP2400 modem, and corresponding "Modem Control" optional circuitry for the ST1, will derive its power
from the ST1 over a special purpose pin on the RS-232 port. To ensure a successful system, select a modem of good quality because modems of lower quality can "lock up" in the field.
 

Cellular phone technologies are now available with modem connections which free up the user from having to install a conventional phone line. The solutions are similar to that described for modems earlier.
Two way paging technology is another recent development which shows promise for remote metering. In these applications the exchange of information in small "packets" are sent during off hour periods to a mailbox in a Network Operations Center of the wireless service provider. Middleware software can then retrieve this information from the mailbox, and then format the information for use by other Windows programs. It is also possible to obtain immediate notice of meter problems on a serviceman's pager. Finally commands may be sent to the remote flow computer from an operator on the host PC.