motorola sp50 roger squelch

I have 2 sp50 radios that I got programmed to work with my radius sp10 radios.
They all work fine except for when I let go of the push to talk button on the sp10, I get a loud squelch noise from the sp50 radios (kind of like a hissing sound). I think it may be something to let the sp50 know that the person on the sp10 let go of the push to talk button (“roger or over”)
The 2 sp50’s don’t do this when used by themselves, they only do it when used with the sp10’s and the sp10’s don’t do this when used by themselves.
Is there a setting in the programming for this not to happen on the sp50’s?


Every radio must be programmed with the CTCSS or DCS codes all the same. They also need to be programmed with the “Reverse Squelch Burst” function. This will give you a perfectly quiet transmission between the radios. Note: The SP50’s require a technician with the correct software and cables. The SP10 uses dip switches. One dip switch determines the frequency and the other one determines the CTCSS code (DCS not available on the SP10).

I had the sp50’s programmed again and they fixed the squelch but now my motorola sp 21 does it when I use them with the sp50’s.
Is there any way of getting rid of the squelch from the sp 21’s?