McWiLL surpasses, both on the level of specifications and on the level of the characteristics of the manufactured network and subscriber equipment, other technologies of professional telecommunications used in RussiaAPCO P-25 – one of the earlier projects for transition from analog systems of trunking communication to digital technologies that was launched in 1989 in the USA.
Elevated power of the radio stations, interference immunity, compatibility with analog telecommunication systems, wide coverage area of base stations make it possible to use APCO P-25 both in high-rise building areas with the high subscriber density and in a rural area with challenging terrain, and in areas where analog telecommunication systems are already in operation.
APCO P-25 is a narrow-band digital telecommunication system used today mainly by law-enforcement agencies and not widely implemented on the market of the systems used for deployment of dedicated corporate telecommunication networks.
What can be attributed to the positive features of APCO-25 is the support of professional-user oriented applications: DMO mode, group calls, establishing user groups, discreet listening, possibility for the dispatcher to interrupt ongoing conversation and to block a user terminal, sending broadcast messages, cyphering and two levels of priority. Main disadvantages of P25 are: low data transmission rate (not exceeding 7.2 Kbit/s), weak protection against message interception and high radio spectrum pollution.
TETRA is an open standard of digital trunking communication developed by the European Telecommunications Standard Institute (ETSI) to replace the obsolete analog trunking communication standard of MPT 1327. The first version of the standard was published in 1995.
TETRA is used by state and corporate customers for building a critically important telecommunication infrastructure. It meets the reliability and security requirements but provides narrow-band capabilities (data transmission rate is up to 40 Kbit/s in the bandwidth of 25 KHz) and does make it possible to implement a reliable data transmission and multimedia services. The departmental TETRA networks in Russia are isolated, they provide only local coverage, and the roaming between these networks is not supported.
DMR, as a project, appeared in 2003, when cellular networks of the second generation (GSM) were fully developed and implemented and the conditions emerged for the transition to the 3G networks (UMTS). This standard allows customers to migrate from analog to digital systems at a minimum expense. All the technological advantages of digital communication methods and signal processing with the exception of the voice duplex communication mode and GPS positioning remain at the same level as in APCO-25. To make this standard similar to cellular networks, the DMR standard was supplemented by technologies for connecting the repeater equipment to the base station. This technology was called IP Site Connect. The digital data exchange rate remained far too low, and, under real conditions, does not exceed 2 Kbit/s. The latter fact limits actually the scope of digital exchange services to the SMS transmission, sending of coordinates and to calling subscriber number identification.with in a wide range of parameters, viz.:
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