CCS7 - what's that?

"CCS" stands for "Callsign Communication System". It was developed several years ago as an optimized alternative to the G2 callsign routing system.
CCS routing may be initiated based on callsigns, but also based on a numeric ID which may easily be entered by DTMF.
Using DTMF codes very quickly became the most common way.
When the CCS-Code was introduced for DSTAR callsign routing, nobody expected that the acceptance would be as high as we see it today.
At the beginning many people brought up arguments like "we have callsigns in amateur radio and do not need numbers", "the current G2 callsign routing is good enough" etc..
However, the system was setup first in the German language area where the DCS reflector system grew very fast and became the leading system.
DCS and CCS are closely connected, the callsign routing system CCS uses the DCS reflector mechanism to connect repeaters together for callsign routing.
CCS Callsign Routing basically connects 2 repeaters transparent together through a virtual reflector.
The DTMF system uses 4-digit numeric codes which provides about 9000 CCS-IDs.
Users and repeaters share the same address space.
Towards end of 2014 it became visible that this address space wont be large enough for future development.
Users of CCS saw many advantages compared to the classic callsign routing,
- where calls are directed blind via repeaters without knowing if there runs a QSO at the other end,
- where reflectors on both sides get disturbed by incoming calls and phantom QSOs where they only hear one side,
- where the adressed recipient has to accept an incoming call within a short timeframe before he can talk,
- where complete callsigns with alpha characters have to be entered to address somebody which is much harder to do in many situations (like when working mobile) than to enter a 4-digit DTMF code to the DTMF keyboard of the microphone.
Beginning of 2015 we saw some legal requirements which forced the admins of the DCS reflector system to introduce a basic registration for users. They decided to use the CCS registration for that. This increased the demand for CCS-IDs again and it run short.
As a first step IDs which had not been used for a longer time had to be re-assigned to allow new users to register - which caused some issues.

We already thought about a new ID system for CCS in 2014, but the fact that a lot of client software would need to be changed always deterred us.
Now the pressure is there, there is no other way, we have to do it!

We could now invent a new system, an own numbering scheme, new database servers, new admin systems, recruit new admins, create new errors and confusion for users.
But we could also use an existing, well designed and good working system which is in use since many years.
When the Digital Voice system "DMR" (Digital Mobile Radio) was introduced to Amateur Radio by the MARC-Group they were facing a system which was not developed for Amateur Radio like DSTAR. One fact was, that it did not allow to use alphanumeric callsigns for routing and identification. However, it is a very good system which fits good to our requirements in Amateur Radio and allows a lot of new developments and activities.
The compromise which is accepted meanwhile by most authorities worldwide is a numeric ID system which assigns an ID unique to a callsign in a public readable database.
Some intelligent OMs defined a structured ID scheme which is based on the "ITU Mobile Country Code" (MCC).
This code is also used in many commercial networks like in telephone networks.
The numbering system uses a hierarchic structure, the 1st digit represents the continent (2=Europe,3=North-America, 4=Asia, 5=Australia/Oceanien,6=Africa,7=South-America). The leading 3 digits identify the country, for example 235 for the UK, 262 for Germany, 310-319 for the United States, 655 for South Africa etc.
In Amateur Radio we use 4 more digits for User-IDs, 3 more digits for Repeater IDs. Some countries use 1 digit after the MCC for a regional structure like for States, Kantone, Bundesländer.

Please find more information on the ITU-MCC at Wikipedia and on the webpages of the ITU.
A complete list of IDs which are used for Amateur Radio may be found here: ITU-MCC by country/prefix here and regional IDs here.

This system provides about 10000 IDs per country, many, many more than the old CCS system.
(We have currently 45000 DSTAR users worldwide registered at the US-Trust system and about 16000 DMR registrations worldwide).
From technical view this 7 digit scheme uses the full space which is available without changes in the CCS network protocol. Together with an additional module ID for private DSTAR hotspots it fits to the 8 digit address field.

There are 2 (DMR-)Registrationsystems available, one in the US for the continent IDs 3, 4, 5 and 7 and one in Europa for the continent IDs 2 (Europa) and 6 (Africa).
This registration systems use synchronized databases and one common address base - one single registration wordwide.
The European system is currently also connected to the the database of the DMRplus-Network. A registration in one of the 2 registration systems is required to be routed in the DMRplus network. The European system provides all registered user and repeater addresses regular to the DMRplus Masters and Gateways worldwide.

We decided to use the existing DMR-IDs also as a base for a new DSTAR ID scheme and called the 7-digit CCS-ID "CCS7".


In practice the users will only get a new CCS-ID.
In national calls to users, repeaters and hotspot modules everything remains the same like today with the 4- and 5-digit codes.
The CCS-system automatically adds the MCC (Mobile Country Code / the first 3 digits) from the sender's ID to the destination address.

DL5DI's DMR-ID is 2625007 (with the MCC = 262 for Germany)

The way how to address repeaters and modules of DSTAR hotspots remains unchanged, the MCC will be added in the same way like shown before for users if the destination has another MCC than the sender. The new system will only allow to use 4 different modules (A-D) for use with DTMF.
We will provide more samples on this and change existing documentation at a later time.
The current 4-digit CCS-IDs may no longer be used in the new system, there would be many collisions with existing DMR-IDs.
Users who already have a registered DMR-ID do not need to change anything on their registration. If you for any special reason should have more than one registered DMR-ID the lowest will be the CCS7-ID!
The CCS7 system won't allow to use more than one CCS ID per callsign, the assignment has to be unique, differentiation for private hotspots or several modems and dongles may be made with the optional module ID.
When the system has been rolled out we will switch the old CCS registration system off.

What has to be done now?
You should register for a DMR-ID now.
This 7 digit ID is your new DTMF-code, 3 digit country code, not used in national calls, and 4 digit individual ID.

What has been released or may be tested until today?
We are moving step by step to the new system.
- Servers have been set up
- a new version of ircDDBGateway with CCS7 client has been released, gateways should be updated as soon as possible.
- the CCS7 protocol specs are available in the files area of the Yahoo Group "DVRPTR" or on request from me (dl5di).

Our schedule:
All hard- and software-systems which connect to the CCS network have to be modified!
We have set up the first new CCS7 servers and will upgrade all others step by step.
Jonathan G4KLX, the author of ircDDBGateway which is the most common DSTAR repeater and gateway software worldwide, has released the CCS7 enabled gateway software.
It is available in the Yahoo-group and on the repository servers.
The old CCS system is not compatible to the new, it will be replaced within next few weeks.
The names of the new servers are CCS701, CCS702 ...
The new protocol specs for developers may be requestet from me (DL5DI). It is available in English language.
During the transition phase CCS and CCS7 may run parallel for a while, the servers will be connected and addresses be translated, but we will keep this time as short as possible. It will cause some confusion for users because they have to use different IDs on the different systems for the same destination. We recommend an update as quick as possible.

The new CCS7-IDs will be required in future to get access to the DCS reflector network, like it is already the case on several servers in Europe. This has legal reasons and is based on some experiences with stupid people during the last year.

21. August 2015

73 de Torsten DG1HT and Hans DL5DI