The 60-meter band or 5 MHz band is a relatively new amateur radio allocation, first introduced in 2002, that was originally only available in a few countries, such as the United States, United Kingdom, Norway, Finland, Denmark, Ireland and Iceland. Over a number of years however, an increasing proportion of countries' telecommunications administrations together with their government and military users have permitted Amateur Radio operation in the 5 MHz area on a short or longer-term basis, ranging from discrete channels to a frequency band allocation. At the closing meeting of the 2015 ITU World Radiocommunication Conference (WRC-15) on 27 November 2015, amongst the Final Acts signed into the International Radio Regulations was one approving "A Worldwide Frequency Allocation of 5351.5–5366.5 kHz to the Amateur Service on a secondary basis". The ITU's enhanced band allocation limits most amateurs to 15 watts effective isotropic radiated power (EIRP), with some countries allowed up to 25 W EIRP. The ITU allocation came into effect January 1, 2017, after which each country's national administration must formally revise their rules to permit amateur operation. Prior to WRC-15, all 5 MHz Amateur allocations made by individual administrations were in accordance with Article 4.4 of the ITU Radio Regulations, which requires non-interference with other radio services. Where two-way amateur radio communication is authorized on 60 m, it has generally been within the frequency range 5250–5450 kHz, but the whole of this range is not necessarily available and allocations vary significantly from country-to-country. This has been particularly true in latter years since the award at WRC-12 of the range 5250–5275 kHz to the Radiolocation Service, thus effectively reducing the former frequency range down to 5275–5450 kHz. In some countries the allocation is still channelized at present, whereas others have block or band allocations or a mixture. Voice operation is generally in upper sideband (USB) mode to facilitate inter-communication by non-amateur service users if necessary. In the United States and its territories and possessions, channelized USB is mandatory. Where channelization is used, the USB suppressed carrier frequency (a.k.a. 'dial' frequency) is normally 1.5 kHz below the quoted channel frequency. For example, 5403.5 kHz is the 'dial' frequency for the channel centered on 5405 kHz. The "center" of the channel is based on the assumption that the bandwidth of SSB transmissions are 3 kHz, at most. Transmitters that are capable of wider SSB bandwidths should be adjusted for 3 kHz bandwidth