It was specified by Nordic telecommunications administrations (PTTs) and opened for service in 1 October 1981 as a response to the increasing congestion and heavy requirements of the manual mobile phone networks: ARP (150 MHz) in Finland and MTD (450 MHz) in Sweden and Denmark and OLT in Norway.
In 2011, it was covered by The Gamits on a split with Red City Radio.
The song appeared on the soundtrack of the 2006 video game True Crime: New York City
Cavalier offers a number of different business telephone service plans for both local and long distance calling. Rates vary based upon the number of optional features added to supplement basic telephone service. Residential services are provided, but the company does not accept new residential customers.
Cavalier currently provides voice, data services to businesses, residential, and government customers on a private network. In 2012, following a series and mergers, acquisitions, and failed services by CavTel, one dissatisfied business service customer began a blog entitled CavtelSucks.com to document his attempts to part ways with the company.
Many different types of equipment have attempted to replace sound-powered telephones on ships, however, due to the rugged, reliable and power-free nature of this form of communication equipment, it is still in use on all U.S. military vessels, commercial vessels and work boats.
These types of systems allow for two or more parties to be able to talk to one another in areas that experience loss-of-power or when radio communication is hampered by RF signal losses and/or limitations.
A sound-powered telephone circuit can be as simple as two handsets connected together with a pair of wires, which is defined as the "talk" portion of the circuit.
A common approach to transducer design is the balanced armature design because of its efficiency. The number of simultaneous listeners is limited because there is no amplification of the signal.
The microphone transducer converts sound pressure from a user's voice into a minute electrical current, which is then converted back to sound by a transducer at the other end.