DMR IDs

DMR ID's

I've been getting more into amateur DMR and of course you need an ID. Radioid.net is the DB for this of course, but the scheme in use was developed by DMR-MARC. They came up with some convoluted scheme back in the day using Mobile Country Codes as a prefix to segregate the ID's so uses could load only the countries they wish in their contact lists. There is no hierarchical authority (ala DNS) where Radioid.net passes off lookups to country (or lower) levels, and the entire DB stands at under 1mb as text, so this segregation is simply for the users.

DMR ID

First some words on the DMR ID from the specs. It's simple, a 24 bit number, however certain types of DMR systems only use the first 16 bits (Cap Plus trunking for one). Hams tend to use the entire 24 bit ID, and it's typically represented at decimal.

24 bits = 16,777,215 possible ID's

16 bits = 65,536 possible ID's for cap plus

DMR-MARC scheme

DMR MARC's scheme uses the Mobile Country Code ("MCC") as the first part of the ID in decimal, then one digit for sub-country (State), and 3 decimal digits for the user.

First doing this as decimal means we cannot use any ID over 9,999,999 as MNC cannot begin with a 1, thus we're limited to the 7 decimal digits. This removes 6,777,216 ID's from the scope of use.

Another issue is using a 3 digits for the MCC. There are only 226 MCC's leaving 774 blocks of 10000 ID's unused or 7,740,000 total ID's unable to be used. (actually a bit less than this due to the next issue)

Sub Country level (state/province)

In the MMMSUUU decimal format there is only a possible number of 10 sub country levels. This is an issue for many countries which have more than 10 sub-regions. What is done here is to invent

awk to process dmrid file

awk -F\; '$1 !~ /^1/ && length($1) == 7 { print }' dmrid.dat |wc
 184388  184388 2870086