Most ETC systems use the Global Standard for Mobile Communication (GSM), its sub-standards like the Short Messaging Service (SMS) and its advancements like the General Packet Switch Radio (GPRS), Enhanced Data Rate for GSM Enhancement (EDGE) or the Universal Mobile Telecommunication Standard (UMTS). While GSM, SMS and GPRS offer good basic services all across Europe to implement ETC systems, EDGE and UMTS with enhanced data rates may boost functionality but are not yet everywhere availlable.

GSM is the most popular mobile communication standard world wide. It is estimated that more than 80% of all mobile phone users use this standard. The majority of GSM networks utilise the 900MHz or the 1800MHz bands. However some countries on the American continent have to use the 850MHz or the 1900MHz bands, as the traditional 900MHz and 1800MHz frequency bands had already been allocated to other services. FELA uses Quad-Band technology to make OBUs compatible for world wide use.

The Short Messaging Service (SMS) is a communication protocol within the GSM standard to send and receive text messages. Such messages may contain up to a maximum of 160 characters per SMS. SMS uses the Signalling Channel of the GSM network to transmit the data. It is, for example, used in the German "LKW-Maut" System to transmit all Toll related data from the OBU to the TollCollect Processing centre.

GPRS is a packet oriented enhancement of the GSM standard. Depending on the current utilisation of the communication channel between the base station and the hand-sets, it provides data rates from 56kbit/s up to 114kbit/s.