Robustel M1000 Pro V2 User Guide - Manual (Page 51)

Robustel GoRugged M1000 Pro V2 User Guide
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Chapter 4. Typical Applications
4.1 Overview
Cellular data transmission is an increasingly attractive mechanism for communication with remote, non-permanent
or mobile devices. Being able to collect and distribute data virtually anywhere without requiring the limitation of
working within specific fixed line networks is a powerful force for efficiency and reliability. However, the fact that
cellular data is metered means that the frequency of transmission and amount of data sent in each exchange can
have significant cost and performance impact.
In order to understand this impact, let us start with a fairly typical example, where there is a device in the field and
an application on a server at a central site location that collects information from that device.
In general, the purpose of communication with the device will be for one of two reasons:
• Monitoring - Status monitoring data, such as the level or temperature of a storage tank, the velocity and pressure
of a pipeline, the condition of a controller or the status of a register.
• Transaction data – Discrete event data, such as cash or credit transactions, PBX call records or mission-critical and
safety related alarms.
Status monitoring data is often “polled.” The application sends out periodic queries and gets responses to those
queries. The application can usually retry if it does not get an answer, and determine that a problem exists if it does
not get a response after a certain amount of retries.
Discrete event data is usually “unsolicited.” The application does not expect to get information on any regular basis,
and therefore the failure to hear from the device is the normal case (though some sort of “all is well” message may
be sent at a longer interval).
Most applications will likely involve one or both of these methods and data is transmitted in TCP or UDP packets.