I haven't played around with the flex keys at all, couldn't find in the manual how to program them. I just have the phones set up on a test system on the bench right now anyway so there is no dial tone to make outbound calls, just the three wireless phones to intercom back and forth. My office is at the end of our building but I imagine if I put the base unit in the middle of the building, I would get coverage throughout the entire office complex and most of the marina outside, very impressive range.

Travis

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