GP900

General Information

Lab RSS is RVN4097SP. It is not widely known there is Lab software available for this radios!

The programming cable is available here. You will notice it is the same as the MT2000 radios.

You may want to look at the schematic for the RKN4035D Service Cable. This is the actual Motorola cable used for programming and servicing this radio.

The individual part numbers for the components of this cable are listed below.

Reference Part Number Description
C1 21-84008H06 Capacitor, 33nF
1 09-84538E03 Receptacle, 25pos
2 15-80349B36 Housing, Connector
3 30-05118W01 Cable, 13 Conductor
4 01-80754A26 Plug Assembly
5 42-10217A24 Strap, Tie
6 38-80373B24 Protective Cap
7 04-10058B12 Washer, Nylon
8 42-05184R05 Strain Relief
9 22-05541V01 Pin, Latch
10 41-05538V01 Spring, Latch
11 55-05536V01 Latch
12 15-05691W08 Housing, Connector
13 32-05533V01 Seal, Baseplate
14 32-05472P11 Gasket, "o" Ring
15 64-05241X01 Baseplate
16 39-05895V04 Contact, (13)

2 to 16 Channel Conversion

You can convert a 2 channel radio into 16 channels, but there are sacrifices... namely your serial number.

You will need to borrow a 16 Channel GP900 radio. Using MTSX Lab, load up the codeplug from the 16ch radio using the No-Pack/Unpack facility. When loaded, connect the 2ch GP900 radio and program the data to the radio. You will get an error on the PC, but just ignore it.

The 2ch radio is now exactly the 16ch radio, Serial number, Model, CodePlug and Service Settings are also copied, so make a note of the existing settings before dumping the new plug into the unit.


Intrinsically Safe Radios

You will find that if you have these radios, you cannot read them using the GP900 RSS EVN4140 version R05.00.00 (DOS based software).

Subsequent weeks of searching has lead to another version of RSS for a Europe Version of the GP900. Locally known as the FUG11b. This radio seems to be specifically German in origin, badged as a GP900 and identical to the UK model. This uses RSS EVN4173A R01.07.00 (Windows based software).

Unfortunately, this does not read the intrinsically safe GP900's either. The FUG seems to have the same specifications as the UK intrinsically safe radios I have, but the RSS does not read these UK radios, Invalid Model Number appears on computer screen after the radio data has been read.

The GP900 intrinsically safe models all require EVN4140 R06.00.00 or later to program as only this RSS has the bug fixes and extra functionality required for CENELEC. This is why it cannot be read with previous versions. These all state 'Unknown Model', when trying a read/write.

These radios are only 1 watt RF output and cannot be converted to 5 watt by changing the PA module. The CENELEC PA block has less pins!

These radios will not work from conventional batteries! They must be specifically IS marked. The IS battery offers a split rail supply 6.2VDC at limited 200mA for the RX section and 7VDC at limited 1A for the TX section. If a conventional battery is used it will appear as there is no TX output. Conventional batteries only supply voltage to two pins on the three way stud connector, it happens that this only applies volts to the RX section on an IS radio. A link inside the radio to short the RX and TX supply contacts to provide voltage to all the radio sections is the finest cure. Note however this is only for use outside CENELEC considerations.

A point to note is that if a CENELEC battery is used on a non-IS radio it will have a reduced capacity, for effectively you are only using the current limited RX portion of the battery. Do not try any type of force charging with unusual currents or voltages on an IS battery as it will certainly damage the current restricting circuitry inside the battery.


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