From The RadioReference Wiki
MPT-1327 is a industry standard for trunked radio communications networks. It was developed in 1988 by the British Department of Trade and Industry (DTI), and is primarily used in the United Kingdom, Europe, South Africa, and Australia. It uses analog audio on talk channels, and can therefore be monitored by commercial scanners, but no scanner presently decodes the control channel, so true trunk-tracking is not supported - though Winradio and external computer-controlled scanning of MPT-1327 systems is possible.
Systems based on MPT 1327 generally consist of several radio channels. At least one of these channels is defined as the control channel (CC) and all other channels are traffic channels (TCs). Data messages between mobiles and the network are exchanged on the control channel at 1200 bits per second. Each subscriber in an MPT-1327 trunked radio network has a unique call number. It consists of a prefix (3 digits), the fleet number (4 digits) and the subscriber’s call number within the fleet (2 or 3 digits). After it has been entered the call number will be converted in the mobile to a 20-bit address.
For the duration of his call, a subscriber is exclusively allocated a traffic channel from the available trunk.
The different types of communications on an MPT-1327 network and their definitions:
- Mobile-mobile in a cell
- Mobile-mobile in different cells
- Mobile-line access unit via landline or radio
- Mobile-dispatcher station via landline or radio
- Mobile-PABX, Mobile-PSTN
- Status messages on the CC (5-bit data length)
- Short data messages on the CC (186-bit data length)
- Transparent data transmission on the TC (Non Prescribed Data calls)
- Point to point connections
- Group calls with talk entitlement
- Group calls without talk entitlement
MPT-1327 groups and radios are each assigned a unique 20-bit number, consisting of a Prefix (the first seven bits), and an Ident (the remaining thirteen bits). Prefixes range from 0 to 127, and Idents range from 1 to 8100.
In practice, a mobile radio user will never directly use their radio's raw MPT-1327 ID. The mobile radio will convert these numbers to a format defined by a numbering scheme for display to, and entry by, a user. Numbering schemes allow the number space to be further divided into fleets, to enable grouping of particular user groups on a system, in a similar way that area codes are used to divide telephone numbers.
- MPT1343 - the most common form of numbering. Mandatory on UK Band III, and used on most other networks.
MPT1343 numbers are in the form of Fleet Prefix/Fleet Number/Unit Ident (FP/FN/UI) for individual unit numbers, and Fleet Prefix/Fleet Number/Group Ident (FP/FN/GI) for group numbers, where Fleet Prefix ranges from 200 to 327, Fleet Number ranges from 2001 to 6050, and for individual radios, the Unit Ident ranges from 20 to 89 for a small fleet, or 200 to 899 for a large fleet. Group Idents range from 90 to 99 for a small fleet, or 900 to 998 for a large fleet.
For example: 201/2003/200
Group Ident 999 is reserved for an Emergency Phone Number eg., 999 (UK), 911 (USA), 000 (AU) etc.
- ANN - Actionet Numbering, mainly used on networks employing Nokia Actionet infrastructure
- 3RP - Used on networks in France
- CPSX - Used by Chinese police, but rarely seen elsewhere.
French MPT1327 systems may use a signaling variant with an inverted bit stream and different sync patterns in the messages: SYNC=0xB433 and SYNT=0x4BCC..
Can This Mode be Decoded/Trunked?
Currently no scanner can trunktrack a MPT-1327 system. However there are applications that can - see our Trunked Radio Decoders article for more information.