Service & Support

MPH Radar Protocol:

In consideration of other manufacturer's that would like the ability to interface with our
MPH Industries radar units, we are providing the protocol of our units. Please feel free
to use this information.

1  Speed Packet Protocol

The Radar message packet consists of 7 bytes @ 1200 baud, no parity, 8 data bits, 1 start bit.

Messages are paced at 250mS intervals and are sent whether there is a target or not.

1.1  Radar status byte

Neither antenna being selected indicates standby.

Both antennae selected indicates a self-test is in progress. Test results are not sent, the radar either returns to normal operation if successful or ceases communication in the event of failure.

1.2  Alternate Speed

If the alternate mode bit is set, the alternate speed should be displayed. This will be fastest if in opposite direction or slow if in same direction.

1.3  Message Receipt

Each message received should be time stamped and removed after 1 second if it has not been replaced by a new message. The only exception is the self-test message, which allows 8 seconds for the test to complete.

1.4  Example

Received sequence: 0x02, 0xF4(244), 0x32(50), 0x63(99), 0x4B(75), 0x01, 0x03

This would indicate:

• Front antenna
• moving mode
• fastest mode
• opposite direction mode
• patrol speed of 50
• strongest target at 99
• locked speed of 75
• no fastest target (since the value is less that 4)

2  Recommendations for remote displays (sign boards) or dataloggers

• Look first to the lock speed, if it is 4 or above display it otherwise display the target speed.
• If messages are not arriving, blank screen after a few seconds. The radar is probably off, or not connected.
• With the "approach only" antenna, ignore the status byte.
• We recommend some displayed difference between the sign receiving a speed of zero and not receiving a message at all. This makes troubleshooting easier. We display a dot if communications are working.

3  Pinout Description

The following is the pinout for the Python, Speedgun and BeeIII communications connector.