P25 is a digital standard for public safety-level two-way radios. Provide a very high level of encryption, relay format, GPS and over-the-air programming, and combine them in a format widely accepted in the industry. This format guarantees that if the two-way radio is P25 standard, it can be used with other P25 standard two-way radios even from different manufacturers. This allows the police, fire and other public safety departments to communicate with each other in emergency situations while still maintaining their private networks in daily operations.
DMR (Digital Mobile Radio) is a private industry version of the digital standard. It is guaranteed that the radios of multiple suppliers designed using the DMR standard can be used in conjunction with each other. The Tait DMR two-way radio will be used with Hytera, Vertex Standard and MOTOTRBO. This provides flexibility and healthy competition when customers are trying to decide which product to buy. The DMR standard provides functions such as one-to-one, one-to-one, group calls, GPS, and text messaging, creating a new practical level for two-way broadcasting.
DMR equipment can be divided into three levels
The first level equipment is used for cheap digital walkie-talkie applications
The second level equipment is prepared for professional modes such as peer-to-peer mode and relay mode
The third level is used for professional trunking communication mode, in which the first and second level devices use confirmed and unconfirmed data transmission services, and short data transmission services.
For Level 3 equipment, confirmed and unconfirmed data transmission services are used on the service channel, while short data transmission services are used on the control channel. Although DMR, TETRA, P25 and MPT-1327 are all based on open communication standards, they are also They have different protocols and target markets (for example, TETRA and P25 are widely used by public safety organizations) and are not technically compatible.
Another standard dPMR formulated by ETSI is mainly for the low-power, civilian free frequency product market. It is more suitable for personal use, entertainment, small-volume retail and other users who do not require broadband coverage or advanced feature settings.
DMR has some characteristics, such as excellent audio performance, reduced basic equipment costs, longer battery life, fully open and widely supported standards to ensure supply reliability, etc.
DMR digital technology can better suppress noise, especially at the edge of the coverage area, with better voice quality than analog technology. These advantages are all due to the application of narrowband codecs and digital error correction technology.
Another advantage of DMR TDMA technology is that only one repeater, one antenna and one duplexer can have two channels. Compared with FDMA, dual-slot TDMA allows you to get double bandwidth efficiency of 6.25kHz. , At the same time, the investment in repeaters and combined equipment is minimized.