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 §8.2.2.2 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.