GeoSIM, the specialist global SIM card supplier, has launched a machine to machine (M2M) service which allows devices to talk to each other across the world using the GSM mobile network.

The service is mobile-network independent and operates worldwide in over 220 countries on more than 550 networks, and enables devices to pass data back and forth or directly to a customer’s server or web page. The new service does not require a GPRS or 3G mobile connection, but utilises an existing USSD ‘circuit’ on any GSM network.

GeoSIM’s global USSD M2M service enables a very fast method of passing data between remote devices and sensors directly to a server or web page, and it costs the same price no matter where in the world the message is sent from or to.

Ed Neal, managing director of GeoSIM, said, "USSD is virtually instant and only has a delay of a few milliseconds between the message leaving the remote device and reaching its destination. The costs are based on a per-message basis and avoid all mobile data roaming charges that exist when using a GPRS or 3G data connection. The service is ideally suited for adhoc message type data where a continuous flow of data is not required. This suits applications where the device may only be sending data intermittently, in low volumes or being used to remotely control devices."

GeoSIM’s customers are developing applications using the service for a variety of applications, including monitoring fridge temperatures, shipping channel navigation light monitoring, fuel storage-tank level monitoring, asset tracking and remote worker location.
Ed continues, "USSD does not need a GPRS mobile data connection which means that, provided the GSM device is registered on a mobile network, then it’s ready to send or receive data. Power consumption is also much less, meaning that battery-powered devices can communicate for much longer between battery recharge cycles. "

USSD message length is similar to SMS (182 alphanumeric characters in length) and can be thought of as an ‘instant SMS’ but without the delays or non-delivery issues SMS can suffer from. Unlike SMS, USSD messages create a real-time connection which allows a two-way exchange of a sequence of data. This makes USSD more responsive, reliable and often cheaper than services that use SMS, particularly when the device is in a mobile roaming scenario.