GPRS-T1 and GPRS-T2 Modules
One of the basic requirements with respect to the security systems is their capability of reliable and effective information transfer. There are many ways to provide alarm communication, e.g. by using the traditional telephone line, Ethernet network, GSM/GPRS communication or by means of a dedicated radio link. The most widespread solution is by using the telephone line and a communicator which is usually incorporated in the majority of contemporary control panels.
Consequently, this solution is relatively inexpensive, but has a number of drawbacks, especially rather high tamper susceptibility (due to its virtually unprotected infrastructure) as well as unfavorable settlement scheme. Using the Ethernet network for information transfer from the security alarm system eliminates the problem of cost charging, but it is still quite vulnerable to intentionally inflicted damage. The dedicated radio links may be a good and efficient solution, but its implementation is often hampered by lack of unified standards and limited transmission range. Under such circumstances, it is worthwhile to take a closer look at the possibilities offered by GPRS technology. Its main advantages include wide availability (constantly developing mobile networks offer packet services to most of their subscribers) and low operating costs, directly connected to the volume of data transferred, which is small in case of security alarm systems.
In order to make use of the benefits offered by this technology, the security alarm system must be fitted with a suitable communication module. Very helpful in this respect are the SATEL developed GPRS-T1 and GPRS-T2 communication modules. The similarity between names of the two devices is not accidental: both of them offer the GPRS communication capability for virtually every control panel, albeit they differ by their connection method and versatility.
Design of the GPRS-T1 module provides for direct connection of the device to the telephone communicator of control panel. In this configuration, the monitoring data sent by the control panel in one of the popular formats are received by the GPRS-T1 module and forwarded by means of the GPRS (or SMS) communication. Such a solution enables sending a very detailed reports, which are only limited by the functionality of built-in dialer and the specification of selected transmission format. Additionally, it is possible to select the control panel events which will be notified by SMS or CLIP message so that easy-to-read information on vital system events can be received.
The GPRS-T2 model is an even more versatile device: it uses 5 inputs connected to the suitably configured outputs of the control panel. On activating the particular output, the module will automatically send corresponding messages to the monitoring station, either by means of GPRS transmission, or through SMS. The module can be used in much the same way for SMS or CLIP notification. Owing to this method of connection, the GPRS-T2 module has many applications, ranging from very simple alarm control units to independent supervision of automation equipment. An extra advantage of this type of module is the capability of using the analog voltage signals for which lower / upper voltage thresholds can be defined to trigger a predetermined action. Its rich configuration options as well as its single output control feature enable the module to be used even as an absolutely rudimentary alarm control panel.
Both the GPRS-T1 and GPRS-T2 modules have been built on the basis of the well-proven GSM module, which is also used in the latest INTEGRA 128-WRL control panel. Since the GSM module has no active SIM locks, it can be used in the networks of all operators. For their correct operation, the GPRS-T1 and GPRS-T2 modules require the usual 12V DC alarm power supply, so they can be powered directly from the alarm control panel.
The module operating parameters are configured by means of dedicated software. It can be done by using the suitable cable connection to the computer RS-232 port or, which is a great advantage of the new SATEL's devices, by means of a remote GPRS session. In the latter case, the computer from which the configuration is to be done must have an active Internet connection through which the communication will be effected.
It should be borne in mind that, if full monitoring functionality of the GPRS modules is to be used, the monitoring station must be equipped with a suitable TCP/IP receiver. For receiving the information, it is possible to use the SATEL STAM-2 station fitted with STAM-1xE series cards or (in case of other monitoring stations) the SMET-256 device. It is also essential that the station should support the feature of receiving the SMS monitoring reports, which can be used as an emergency communications path.
To sum up, the GPRS transmissions are an ideal alternative to the traditional monitoring through the telephone line, both in terms of the operating costs and the reliability aspect. The important thing about the GPRS-T1 and GPRS-T2 modules is that they enable making use of the GPRS technology benefits even in case of devices which were never adapted for this type of communication.
