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Revision as of 09:17, 29 May 2005 by Scanner freak
Type II Talkgroup Conversions
The easiest way to convert talkgroups between their various formats is by using the Windows scientific calculator. It provides a Decimal to Hex function that works very well.
Type II talkgroup IDs come in three flavors:
- Uniden Trunktracker format such as 41072.
ID Range: (0 - 65504)
- Motorola 3 digit Hex variety such as A07.
ID Range: (000 - FFE)
- Motorola 6 digit decimal variety such as 802567.
ID Range: (800000 - 804094)
In the following formulas, M3 represents a Motorola 3 digit Hex format value, M6 represents a Motorola 6 digit decimal format value, and U represents a Uniden format value.
- The notation Dec_to_Hex(X) means convert X to its Hex equivalent.
- The notation Hex_to_Dec(X) means convert X to its Decimal equivalent.
To convert Use this Formula
- M6 to U (M6 - 800000)*16 = U
- M6 to M3 Dec_to_Hex(M6 - 800000) = M3
- M3 to U Hex_to_Dec(M3)*16 = U
- M3 to M6 Hex_to_Dec(M3) + 800000 = M6
- U to M3 Dec_to_Hex(U/16) = M3
- U to M6 U/16 + 800000 = M6
- Convert the M6 format ID, 802617 to U format:
(802617 - 800000)*16 = 41872
- Convert the M6 format ID, 802617 to M3 format:
Dec_to_Hex(802617 - 800000) => Dec_to_Hex(2617) = A39
- Convert the M3 format ID, A39 to U format:
Hex_to_Dec(A39)*16 => 2617*16 = 41872
- Convert the M3 format ID, A39 to M6 format:
Hex_to_Dec(A39) + 800000 => 2617 + 800000 = 802617
- Convert the U format ID, 41872 to M3 format:
Dec_to_Hex(41872/16) => Dec_to_Hex(2617) = A39
- Convert the U format ID, 41872 to M6 format:
41872/16 + 800000 = 802617
Type II Special Status Bits
Type II Smartnet systems use these status bits for special transmissions such as Emergency, Patches, DES/DVP scrambled transmissions, and Multiselects on Motorola Trunking systems. Motorola Trunking radios directly interpret them for their special functions, thus no difference is noticed by the person with the radio. The Trunktracker scanners however interpret these special talkgroup status bits as different talkgroups entirely. Below is the conversion chart for these special status bits.
- TTID + # Usage
- ID+0 Normal Talkgroup
- ID+1 All Talkgroup
- ID+2 Emergency
- ID+3 talkgroup patch to another
- ID+4 Emergency Patch
- ID+5 Emergency multi-select
- ID+6 Not assigned
- ID+7 Multi-select (initiated by dispatcher)
- ID+8 DES Encryption talkgroup
- ID+9 DES All Talkgroup
- ID+10 DES Emergency
- ID+11 DES Talkgroup patch
- ID+12 DES Emergency Patch
- ID+13 DES Emergency multi-select
- ID+14 Not assigned
- ID+15 Multi-select DES TG
Therefore, if a user was transmitting a multi-select call on talkgroup 1808, the trunktracker would actually receive those transmissions on 1815. Some common uses of these status bits are as follows:
When a user hits their emergency button, all conversations on the talkgroup revert to the Emergency status talkgroup (ID+2) until the dispatch clears the emergency status.
Therefore, if someone hit their emergency button and their radio was on talkgroup 16, all communications would switch to talkgroup 18.
A lot of Fire and EMS departments dispatch tone-outs and alarms as Multi-select communications (ID+7). Therefore, if your fire department dispatch talkgroup is 1616, and they do dispatch tone-outs and alarms as Multi-selects, then those communications will be on talkgroup 1623.
This can be a problem, because you will miss communications if you don't have those talkgroups programmed.