Frequently Asked Questions

About SMS/GPRS messsaging, GPS positioning and our GSM controllers

Q: Why does EMM-Tek use GSM SMS (text messages) instead of GPRS (General Packet Radio Service)?

A: The RMC301 and similar products from EMM-Tek are designed for use in applications that require the periodic sending and receiving of relatively small amounts of data (input status, GPS position etc.). The emphasis for these products is low power consumption by the device rather than high data rates. GPRS is better suited for applications that involve real-time, two-way communication and the transfer of larger amounts of data. Typically SMS coverage is much wider than GPRS coverage which means that messages to or from the RMC301 are more likely to get through compared to a GPRS service. See our White Paper for a more detailed discussion of this topic.

Q: Can EMM-Tek can provide systems with GPRS/FTP/UDP/HTTP-Push data links?

A: Yes. Please get in touch and we'll be happy to discuss your application needs in more detail.

Q: Where can EMM-Tek systems be used?

A: Almost anywhere in the world that has GSM coverage. GSM is used throughout the world but coverage is more limited in the USA and Japan where other standards were previously used. To check coverage in any international location please check this useful site.

Q: There seem to be different frequency bands around the world, do EMM-Tek products work on all GSM frequencies?

A: Yes. EMM-Tek products use Quad Band GSM chip-sets that will work automatically to switch to the appropriate frequency band. Those bands are 850MHZ, 900MHZ, 1800MHz and 1900Mhz. These are the most often used bands although some others are defined.

Q: Can EMM-Tek devices be used at sea?

A: Our systems can be used wherever there is a reliable GSM signal. The coastal regions of most countries, using GSM, have coverage to around 8-10 miles offshore but this will depend on local conditions. If you need a system to work offshore it's useful to use a high gain antenna for best reception.

Q: Can EMM-Tek devices be used in a car or vehicle?

A: Yes. A lot of our customers install EMM-Tek products into vehicles that need to be tracked using GPS. Ask us about specific applications where a 24V supply is used in the vehicle.

Q: What is the antenna connector size and style?

A: The antenna connector on our cased products is SMA female. Other types of connector can be fitted by special order. Please contact EMM-Tek to discuss.

Q: Can I use any GSM SIM card with EMM-Tek products?

A: Generally yes. However because user set-up information is stored on the card, older cards with fewer than 100 storage locations will not work correctly.

Q: How do I connect power and sensor leads to the EMM-Tek products.

A: On the Lite (L) products, users solder leads directly to the PCB. This is recommended for qualified personnel only. On the standard products, connections are made by means of screw terminals inside the case.

Q: Do I need a mains supply to power EMM-Tek products?

A: Generally no. Our systems will run from a DC supply of 5.5V to 30V. Since EMM-Tek systems are designed to be low power, it is possible to use a solar panel (photovoltaic) and rechargable battery to supply power in remote locations.

Q: Can I run EMM-Tek products on regular alkaline cells?

A: Yes you can. We recently ran an experiment (not very scientifically) where an RMC301 (without GPS) was powered from 6 AA size 1.5V cells (own label supermarket grade product) connected in series. This gave the system a nominal 9V supply. We set the unit to send a Status message every 5 minutes and set a low level alarm for when the battery voltage dropped to 7 Volts. In this mode the RMC301 ran for more than 30 hours and in that time sent more than 360 SMS messages. It ran for another 10 hours before the battery dropped below 6V. Results may vary with this test depending on the amount of power needed to communicate with the GSM base station.

Q: Can I connect a PIR (Passive Infrared) detector to the RMC301?

A: Yes. The latest version of the RMC301(v4) has made it very easy to connect PIR or indeed any 'no-volt' external contact to the RMC301. Magnetic door switches, pressure mats etc can all be used.

Q: Do GPS enabled system need an external antenna?

A: No, the antenna is integrated.