A blog about MOTOTRBO and other things.

11 February 2015

Colour Code?

In digital mode, all MOTOTRBO radios support a feature known as Color Code (USA: Color, everywhere else: Colour). In fact this is defined in the ETSI DMR standard.

In a MOTOTRBO radio or repeater, there is a color code field which allows the selection of one of 15 colour codes. A radio which has been programmed with colour code 1 will not be able to transmit on a repeater configured with colour code 2 and so forth. A radio can be configured with multiple colour codes - one for each channel. A repeater can only be configured with one colour code.

Colour code is useful because it can prevent radios from one site or system mistakenly roaming to another site or system which uses the same frequencies. Although there is activity from the neighboring system, the radio will ignore all transmissions from the other system because it has a different colour code.

This is also useful for telecommunication regulators who have to allocate the same frequency to two DMR licencees in the same region. The regulator simply has to specify a colour code in the licence conditions - much like PL/DPL was used in analogue as a guard tone.

There is a limitation of course, if two geographically adjacent radio systems use the same frequencies, yet use a different colour code, there will be audio quality issues in the area where radio users are able to receive signals from both systems at roughly the same signal strength.

MOTOTRBO radios can also be configured to be "polite" to other systems using the same frequency. In the CPS, it is possible to set the TX Admit Criteria to be Color Code Free. This will only permit the radio to transmit if there is no signal, or if the signal present on the receive frequency has the same colour code.

On simplex channels which employ DCDM, colour code 15 is reserved for inter-radio synchronization signaling - so only 0 to 14 may be used on systems that use this feature.

Although not intended for this, colour code also provides an additional mechanism to prevent casual eavesdroppers. More determined (resolute) eavesdroppers will however be able to determine the colour code using a scanner and a decoder application. In such cases Enhanced Privacy or 256 bit AES should be used.

19 January 2015

Because it's more than push to talk...

Motorola's Application Developer Programme allows software developers to create outstanding applications for customers to harness the true potential of MOTOTRBO. The Application Partners have proven expertise and are committed to deliver wold-class applications for use in a wide range of industry and government sectors (read more about this here).

These applications, combined with Motorola's extensive experience in radio systems and critical solutions, produce the power behind the delivered solution. These partnerships enable Motorola's Channel Partners to provide a diverse range of high quality; integrated and customer focused solutions.

Here is a presentation highlighting how these customers have benefited from this partnership. To find out more about Motorola's Application Developer Programme, click here.

Another standard for Intrinsically Safe equipment?

Here is an interesting article - which I somehow missed - that appeared in Mission Critical Communications some time ago. I checked my records and found I was traveling at that time (so I guess I can be excused).

In 2013, the Telecommunications Industry Association released ANSI/TIA-4950. This standard defines the requirements for Battery-Powered, Portable Land Mobile Radio Applications in Class I, II, and III, Division 1, Hazardous (Classified) Locations.

ANSI/TIA-4950 was developed to provide a standalone set of intrinsic safety requirements that address issues unique to two way radio equipment used in both classified and non-classified environments. These requirements however do not impede the traditional levels of RF performance in two-way radio systems.

Certification for ANSI/TIA-4950 is carried out by UL. UL has been involved in hazardous locations certification testing since 1930. They are a well established testing house with a proven track record and expertise in all area classifications, protection methods and product categories.

The Telecommunications Industry Association represents manufacturers and suppliers of global communications networks through standards development, policy and advocacy, business opportunities, market intelligence, and events and networking. TIA is accredited by the American National Standards Institute (ANSI). More information about ANSI/TIA-4950 can be found here.

6 January 2015

The MPT1327 Option Board (Part 3)

Sometimes when programming a MPT1327 radio, it may fail to register on the system or may miss some calls. In all cases, the root cause can be attributed to a configuration problem. Since there are many fields in the CPS, it may be difficult to diagnose the problem by simply going through the configuration once more.

To aid in the tracing of where the configuration problem is, all Motorola portable display model MPT1327 radios have a diagnostic mode which will allow a technician to analyse what the radio is doing. To access this diagnostic mode, press 120# on the keypad. Remember that this only accessible in MPT1327 mode.

Once the 120# key sequence is pressed, the radio will display certain information. This information can be accessed by pressing any of the below numbers.

Pressing 1 will make the radio display the current control or traffic channel number and its RSSI in dBm. If the radio cannot find a control channel, the displayed channel number will be constantly changing (i.e. radio is hunting). The channels that radio searches while hunting for a control channel is determined by the channels in the control channel list in the CPS. If comprehensive hunt is used, the radio will start at 1 and stop at 1023. During the hunt process, if no signal is detected on that channel, the radio will display -255 as the RSSI. If the radio temporarily displays another value, it means that there is a signal (either valid on invalid) on that channel. If you know that, that signal is the control channel and the radio is not locking on, then there is a problem with the system identity in the radio configuration (i.e. the radio sees the control channel but disregards it).

Pressing 2 will make the radio display the system identity, decoded on the current or last found control channel, in hexadecimal. If looking at point 1 above, that signal is the control channel and the radio is not locking on, then there is a problem with the system identity in the radio configuration (i.e. the radio sees the control channel but disregards it).

Pressing 3 displays the number of correct codewords received and the number received with an error. This is effectively the bit error rate, but the measurement is really how many 64bit frames were received and how many were received with an error within the last 5 seconds.
Pressing 4 displays the software part number.

Pressing 5 displays the codeplug part number.

Pressing 6 displays the radio's identity in MPT1327 format. This number must match the number recorded in the trunked system user database. To convert the MPT1327 ident. into MPT1343 see § of the MPT1343 Standard.

Pressing 7 displays the channel number; hunt status; carrier status; hunt level and whether LM2 has been exceeded. The hunt status will either be - or S, depending on whether the radio is hunting for a control channel or not. If a carrier is detected, carrier status will show as C, otherwise it will be a -. The hunt level will either be a - (no signal); 0 (LM0 exceeded) or 2 (LM2 exceeded). Note that the radio will only display this information whilst on a control channel.
Pressing 8 displays the radio (or option board) electronic serial number. This number has the same function as a TEI in TETRA or a IMEI in GSM. It means that if ESN checking is used in the trunked system, the ESN in the user database must match this number. The ESN format is defined in the MPT1327 standard.

Pressing 9 displays the radio model number.
Pressing 0 will exit the diagnostic mode. The radio may display a series of ---, these can be cleared by pressing any programmed button.

Note that this is not the test mode - the test mode is accessed by pressing P2 or side button 2 5 times within 5 seconds of power up. The test mode allows the radio to be tested independently of programming. The diagnostic mode allows the technician to view the radio status and some system parameters.

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.

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