There are two basic formats of Digital two-way radios and the two are incompatible with each other: FDMA (often referred to as dPMR) uses 6.25kHz wide radio channel; therefore half Ofcom license fee. TDMA (sometimes referred to as DMR) uses 12.5kHz wide channel for two timeslots. There is no discernible difference in performance between either technology, ALL use the same speech vocoder (they all sound the exactly the same!). Digital speech quality is not as good an Analogue system, but the usable range is much greater and digital speech processing means it is excellent for distinguishing human speech in noisy environments. With over eleven manufacturers already providing interoperable equipment, dPMR is now in a league of its own in digital PMR.