System Sensor Sync Issue

Having a bit of a problem with this one. Old building with old SK5820 panel with lots existing previous type System Sensor devices like a P241575. These are all tied to a System Sensor sync module. They all worked fine. We tied in (properly) a new System Sensor PC2R ceiling horn/strobe into a point where an old one was demo’ed from (and unfortunately thrown away). Now everything is still in sync EXCEPT the PC2R. My understanding is that old and new System Sensor devices are compatible so I don’t get what’s happening here. Obviously, I’m missing something somewhere. Can anyone help with this one?



Hello and welcome!

Being an older system, I’m assuming the sync module is an original System Sensor MDL module. Is this correct?

My initial thinking is that an odd combination of a very early revision MDL and the newer tech in the PC2R are causing headaches. The current production model, the MDL3, is backwards-compatible with the legacy SpectrAlert series, but the sync protocol may have changed ever-so-slightly from the first MDL runs to the current protocol recognized by the newer models.

In theory, all of the SpectrAlert devices should be compatible, including the Advance series and the legacy devices. In fact, the MDL manual from 2005 explicitly lists the PC2R as compatible. However, all datasheets from 2011 onward list the PC2R as being compatible with only the MDL3 series sync modules, the orignal MDL appears to be dropped entirely.

Are the strobes not in sync, or is the problem with the horns? Newer SpectrAlerts don’t have the long pulse before the Code 3 starts.