Hi beresfoa@sequent.com ,
You maybe running into this hook switch issue.
Cleaning and Troubleshooting Cisco IP Phone Hookswitch
This section highlights some guidelines for phone usage and what to look for if you suspect a hookswitch failure.
A slightly dampened soft cloth should be used to clean or wipe down the phone. Do not use any liquids or powders directly on the phone to clean or for other purposes. As with all but weatherproof electronics, liquids and powders can contaminate the components and cause failures.
Self Cleaning Hookswitch Contacts
The hookswitch contacts design uses a wipe action to self-clean the contacts. Periods of nonuse of the phone allow air impurities such as dust and other contaminants to hinder contact performance, which results in intermittent operation. Press and release the hookswitch rapidly a dozen times or so to clean the contacts.
If none of the solutions above remedy the situation, Return Material Authorization (RMA) the phone.
http://www.cisco.com/en/US/products/hw/phones/ps379/products_tech_note09186a00801c0810.shtml
Please rate if this helps
Regards,
Justin