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New Member

Static electricity on IP-phone?

Several users complained about having a discharge via their ear when they pickup the handset of their IP-phone (CP7940/7960). Anyone knows about this? The phones are inline powered via a Catalyst.

rgds, Geert Folens.

1 ACCEPTED SOLUTION

Accepted Solutions
Silver

Re: Static electricity on IP-phone?

I kept this old notice on this issue:

In some cases, especially in climates of seasonal low humidity, end users of Cisco® IP phones may occasionally experience a minor electrostatic discharge (ESD) from their phone handsets. This document offers suggestions for why these discharges sometimes take place and what can be done to reduce their frequency.

(rest of notice) then this statement at the end:

Cisco IP phones comply with safety standards IEC60950, EN60950, UL60950, and CSA C22.2 No. 60950. In addition, Cisco Systems® has made enhancements to phone handsets to limit the effect of this harmless ESD. If desired, spare handsets may be ordered from Cisco using the SKU CP-HANDSET=. It is best to order this handset directly from Cisco or to have it drop shipped directly from the factory to the customer site.

http://www.cisco.com/en/US/partner/products/hw/phones/ps379/prod_bulletin0900aecd8022be68.html

Mary Beth

4 REPLIES
New Member

Re: Static electricity on IP-phone?

From an NCTI certified professional:

Sounds like it is the good old office feature. Your end-users are picking up a static charge while walking around on carpeted flooring and then touching the plastic case of the phone which then picks up the charge - well it equals out the charge anyway.

This is why several users have complained and not all - because some of the people are discharging on other objects.

To test this, 1) check the phone case with a voltage detector, or 2) place a phone on a wall where the user would stand on a rubber mat or a cement floor - have the users who are complaining about the discharge touch a conductor prior to touching the phone so they are not carrying any charge with them. See what happens.

Also, if the phones/switch is not properly grounded, then a static build-up could be occuring - which you'd see with a voltage detector.

New Member

Re: Static electricity on IP-phone?

Apparently this is a known problem:

It only occurs with older handsets. You can tell the difference between the old and new by the notch under the earpiece that engages the tab when the phone is mounted on the wall. The old handsets have a narrow, square cut notch, and the new handsets have a wider beveled notch.

Cisco Employee

Re: Static electricity on IP-phone?

Who did you find out from? Is there a bug associated with this issue?

Silver

Re: Static electricity on IP-phone?

I kept this old notice on this issue:

In some cases, especially in climates of seasonal low humidity, end users of Cisco® IP phones may occasionally experience a minor electrostatic discharge (ESD) from their phone handsets. This document offers suggestions for why these discharges sometimes take place and what can be done to reduce their frequency.

(rest of notice) then this statement at the end:

Cisco IP phones comply with safety standards IEC60950, EN60950, UL60950, and CSA C22.2 No. 60950. In addition, Cisco Systems® has made enhancements to phone handsets to limit the effect of this harmless ESD. If desired, spare handsets may be ordered from Cisco using the SKU CP-HANDSET=. It is best to order this handset directly from Cisco or to have it drop shipped directly from the factory to the customer site.

http://www.cisco.com/en/US/partner/products/hw/phones/ps379/prod_bulletin0900aecd8022be68.html

Mary Beth

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