Unified field theory 1820 Hans Christian Ørsted discovered that electric currents exerted forces on magnets, while in 1831, Michael Faraday made the observation that time-varying magnetic fields could induce electric currents. Until then, electricity and magnetism had been thought of as unrelated phenomena. In 1864, Maxwell published his famous paper on a dynamical theory of the electromagnetic field. This was the first example of a theory that was able to encompass previously separate field theories (namely electricity and magnetism) to provide a unifying theory of electromagnetism. By 1905, Albert Einstein had used the constancy of the speed of light in Maxwell's theory to
Unified voicemail Unified voicemail Unified voicemail is the combination of different voicemail bearers into a single voicemail system. Using dedicated DID /DDI numbers for each mailbox, the mailbox can be used on a variety of devices and end-points. This is similar to what GSM providers use for their voicemail systems. Mobile phones and traditional analog phones need to support conditional call diversion to enjoy unified voicemail. Unified voicemail can be extended into unified messaging as already used. Some telephone users have several telephone accounts, which may include home, work, mobile, and SIP numbers. Unified voicemail provides a single voicemail for several accounts.