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New Member

7940 IP phone resets intself when a portable radio is keyed within 3 feet

7 REPLIES
Cisco Employee

Re: 7940 IP phone resets intself when a portable radio is keyed

Hmm, interesting problem. Not sure why this would happen. Please provide more details, such as, are you using inline power, does this happen each time, etc.

If this is a recreatable problem,please open a TAC case as we would want to fix this, if it is an issue with the phone.

New Member

Re: 7940 IP phone resets intself when a portable radio is keyed

I am using a external power supply (Cisco Brick). This doesn't happen with other phones at other locations, so I am thinking that it is a problem with some interference of some sort at the location the phone is located. I have already opened a case with TAC.

New Member

Re: 7940 IP phone resets intself when a portable radio is keyed

Could be that the RF from the radio is getting to the phone via the ethernet or power cable. Depending on the power/freq of the radio, I'm not surprised. A lot of electronics is susceptible to RF from 2way radios, 2way pagers and cell phones.

Some versions/models of phones may be more susceptible too.

Wonder what's unique about the one site versus the others....since you don't have it in the one site.

New Member

Re: 7940 IP phone resets intself when a portable radio is keyed

That was my thoughts as well. I swapped out the phone, the ethernet cable and the external power brick, same thing happens. It doesn't happen if the radio is kept out of site of the phone.

Cisco Employee

Re: 7940 IP phone resets intself when a portable radio is keyed

Its likely that there is a floating ground in the ac circuit at this site or ground was lost on conduit. Get an electrician to check it out or get a ground checker from a hardware store (fairly cheap) and check out the circuit. If ground or conduit ground is lost then rf sheilding is lost and RF will induce HF voltage spikes on ac line.

New Member

Re: 7940 IP phone resets intself when a portable radio is keyed

I kinda figured as much, as I don't have this problem with any of my other IP phones at other locations. Thanks for the info. I love this place.

New Member

Re: 7940 IP phone resets intself when a portable radio is keyed

Did you ever get this fixed? I am having the same problem.

Thanks

Frank

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