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Turn your CP-8851 over and look at the ports underneath. If you see a "square" headset port, you'll need to get the RJ-9 version of this headset (SKU:5796300).
I would recommend:
Sorry, there was a problem. Please try again later.Not sure. The headset is made for a landline phone. I am using it with a cell phone, but I had to buy an adapter to work with the cell phone.
Sorry, there was a problem. Please try again later.This headset is compatible with phones that have a 2.5 mm jack.
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