Modem tutorial - what is a modem?
Modem tutorial to explain how modems enable remote equipment to communicate over PSTN, GSM and GPRS networks.
This modem tutorial explains what a modem is and how they are typically used for enabling remote devices to communicate with central locations.
10% off Modem starter kits when purchased from our online shop
With the advent of the Internet, modems are becoming more intelligent. Find out more about inteligent TCP/IP modems through our IP modem tutorial.
Modems for machines
Modems are traditionally associated with PC's in the form of box/PC modems, however this technology is not suited to non-PC equipment or "machines", which have specialised needs: -
- Size - there is little space within many embedded devices for a modem box
- Power consumption - some devices are battery powered and need low power modems
- Environment - machines can be deployed and need wide temperature range.
- Integration - modems need to be integrated within the machine and not external
Modem tutorial - what is a modem?
Modems provide access to field-based equipment
A modem provides the communication interface. It transports device protocols transparently over the network through a serial inteface. A modem adapts the machine to communicate over various networks in order to gain access to the machine including: -
- PSTN - a wireline dial-up network
- GSM - a wireless dial-up network
- GPRS - a wireless "always on" network
Modem tutorial - why use modems?
Modems provide remote access to machines in the field to eliminate unnecessary site visits and provide fast access to information in the machine. However, integrating modems
- Modems are "black art" products, surrounded by complex compliance and regulatory issues. Designing your own modem solutions requires specialised skills.
Using off-the-shelf modems enables designers to focus on their core application strengths, and not be drawn into solving issues that are not related to core competency yielding potentially unreliable products.
Modem Tutorial - typical modem use
comtech offer interchangability between PSTN, GSM and GPRS modem modules
M2M Modems are embedded with the machine and transport higher level protocols between the machine and central location via the network.
- Point to Point "polled" networks where proprietary or industry specific protocols to communicate with central servers.
- TCP/IP enabled remote machines such as Embedded PC's, where modems provide the physical network connectivity.
IInterfacing to modems
M2M Modems are AT-command compatible at the serial interface to the machine and common between many modems.
- Driven and controlled by the remote machine processor using industry standard commands.
- Fast time to market
Modem Tutorial Related Links
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Why use Comtech embedded modems?
Comtech offer a common footprint, which permits interchangability between PSTN modem modules, GSM modem modules and GPRS modem modules.
Comtech eliminate the network compliance issues: -
- Modems for world-wide compliance
- No need for customers to undertake costly Approvals
- Elimates need for developing "black art" communication expertise
Further Information
Further information beyond each tutorial can be found in our telemetry solutions and telemetry products.
This modem tutorial is provided as a resource to aid M2M adoption, other tutorials offer further insight into M2M technology.
