User`s guide

1-3
- Analog cellular phone service has been used in areas where phone lines do not exist.
While the initial purchase price of the service can be higher than that of a wired line
system, it eliminates the expense of running telephone wires over long distances. In
some hazardous sites, telephone lines are not permitted. However, the limited capacity
of analog cellular technology led to the development of digital methods to increase
capacity and provide new features. Some service providers have discontinued, or
greatly decreased the availability of analog cellular services.
- Digital cellular networks are rapidly expanding and replacing earlier analog systems.
More efficient use of the radio spectrum permits the network to handle many more calls
at a given time, and to offer new features including data exchange. In the case of the
DCM-200, a GSM cellular phone link is utilized to provide the most economical and
reliable solution. Figure 1-1 provides a simplified illustration of the network from end-to-
end.
Figure 1-1
Typical DCM-200 System