A blog about MOTOTRBO and other things.

10 April 2015

Frequently asked questions

I get asked all sorts of questions via email; the contact form or through the comments. I've therefore created a list of commonly asked questions - and answers -at http://cwh050.blogspot.com/p/faq.html. Please have a look at this page, your question may already have been answered there.

If you would like anything added to the FAQ page, please add a comment at the bottom of the page.

If you do post a comment, please remember that comments are moderated which means I have to approve them first. The reason for this is that I get a fair amount of comment spam so I need to sift through these beforehand. It means that there might be a few hours or days delay for your comment to appear and for me to reply.

1 April 2015

Backhaul networking, what are you using?

I've been asked by some colleagues at Motorola to find out what our customers are using to connect their MOTOTRBO sites via IP. So far, I've got a number of useful responses but I thought I would open the survey to my Blog-readers.

If you would like to take the survey, you'll find it at http://bit.ly/bh-surv-ext. Please fell free to pass this survey link on to your colleagues and friends.

I am mainly interested in getting feedback from customers in Europe (which includes Russia and Central Asia) and Africa. If you are outside this region, please feel free to submit your answers and select "other" as your country.

Idstein, Germany. My adopted home town.

Just so you know: The survey is an official Motorola activity. This Blog and YouTube channel remains my personal project and therefore the postings on this site, are my own and do not necessarily represent the positions, strategies, or opinions of my employer, Motorola Solutions.

Managing security on your MOTOTRBO network

MOTOTRBO second generation radios supports 3 levels of privacy (encryption): Basic; Enhanced and AES.

Basic Privacy only provides simple 16 bit scrambling and only offers very  basic protection against eavesdropping. There is only one key and this must be the same in all radios that need to be party to a specific call. Radios which dont have this key will hear garbled audio when another user transmits.

Enhanced Privacy uses the well known ARC algorithm - the key length is 40 bits. It is also possible for the radio to be programmed with multiple keys which can be selected by changing the channel. The key is write only so the key variable must be stored in a safe/secure location.

AES 256 bit provides the highest level of protection of all Motorola Professional and Commercial radios. The radio uses a symmetrical group key which this means that the same keys needs to be programmed in all radios that need to be party to a specific call.

Managing your keys is essential. This means (among other things) that the keys must be updated in the radios on a regular basis. For this, Radio Management and OTAP can be used.

It is also critical to ensure that lost or stolen radios (or radios in the wrong hands) are quickly identified and disabled. Radios which are not in use must be secured and not given to anyone who is not authorized to have this equipment.

Apart from key management and radio asset management, it is also essential to ensure that staff who are handing radio communications equipment can be trusted and are not batting for the other team.

It may also be possible for suitably equipped and authorized Application Partners to develop their own encryption algorithm, on the radio option board using their own chipset, if the level of security provided by AES256 is not enough, or another algorithm is preferred.

26 March 2015

Dynamic Mixed Mode

Dynamic Mixed Mode (DMM) allows customers to easily migrate from analogue to digital with minimal disruption. It works by allowing analogue and digital radio users to use the same repeater. 

In DMM, the repeater dynamically switches between analog and digital modes based on the call it receives from radios. If an analogue radio transmits, the repeater switches to analogue mode to repeat that call. However, the repeater only repeats analog calls that are qualified by PL (DPL/TPL) - this is important as CSQ (Carrier Squelch) operation could result in the repeater staying in analogue mode and thus becoming inaccessible to digital radio users. 

If a digital radio transmits, then the repeater switches to digital mode to repeat the digital call if the call uses the right color code. While the repeater repeats one analogue call at a time, it can repeat twp digital calls at the same time, one on each logical channel. The repeater cannot however repeat an analogue and digital call at the same time.

Dynamic Mixed Mode is a repeater only configuration . For radios, one simply needs to configure a scan list containing an analogue channel and a digital channel. MOTOTRBO radios support both analogue and digital operation. 
The legacy analogue radios will not be able to do digital and the technology used in these radios cannot discern between an analogue and digital transmission.  It therefore makes sense to configure these radios with DPL/TPL so that they can block out the digital bursts on the channel during a digital call. It is also adviseable not to use TPL frequencies 67 and 103,5Hz as the DMR transmissions can mimic these two tones.

Dynamic Mixed Mode does not support the following configurations/features:
  • IP Site Connect configuration - This means that in Dynamic Mixed Mode, the repeater can only repeat the digital calls over-the-air and cannot send the voice/data packets over the IP network. The status of the repeater and the control of the repeater cannot be performed from a remote PC application like RDAC-IP.
  • Capacity Plus configuration - This means that in Dynamic Mixed Mode, trunking the logical channels of multiple MOTOTRBO repeaters as per Capacity Plus is not supported.
  • FCC Type-I and Type-II monitoring - Since FCC Type-I and Type-II monitoring are not supported in single site analog operation in any of the earlier MOTOTRBO releases, it is also not supported in Dynamic Mixed Mode single site operation.
  • Transmit Interrupt feature - The Voice Interrupt, Emergency Voice Interrupt, Remote Voice Dekey, and Data Over Voice Interrupt features are presently not supported in Dynamic Mixed Mode systems.
  • RDAC over IP feature - RDAC over local USB and connections via GPIO are supported. RDAC over the network is NOT supported.
  • Repeater Knockdown - In Dynamic Mixed Mode systems, this feature is not supported during an ongoing digital transmission.
  • PTT on a 4-wire interface - In Dynamic Mixed Mode systems, this feature is not supported during a digital repeat operation.

The Author

Please Note

The postings on this site are my own and do not necessarily represent the positions, strategies, or opinions of my employer, Motorola Solutions.

Translate this page

Popular Posts