Legal issues regarding the recording of phone calls must be considered before embarking on voice logging. This varies on a state-by-state basis.

Some states and countries require 'one-party notification' in which only one of the two individuals needs to be made aware that the call is being recorded. This, of course, is most easily done by notifying the call centre agents, and should be part of the employee handbook they receive upon being hired. By their signing off on the handbook, it has been documented that they have been duly notified that the recording will take place. Check with a local attorney familiar with state employment law, as it may be advisable to have a separate sheet signed by each employee, explicitly notifying him or her that calls will be recorded.

The other scenario requires that both parties be made aware that the call is being recorded; these are called "two-party notification" states. This can be accomplished by playing a preamble recording on every call or inserting a periodic beep tone. The preamble recording is common, but it may prove to be a technical challenge to do so on every account. There is also the concern of how to respond to clients who object to an automated announcement before every one of their calls. Typical verbiage for the announcement or preamble recording is, "Thank you for calling ABC Company. Your call may be monitored for training or quality assurance purposes."

…Several websites contain information about notification; unfortunately, they are not in complete agreement… Regardless of their information, be sure to consult a local attorney before recording any phone calls.

Also, there are privacy concerns and issues. In general, one should take every possible precaution to avoid recording personal phone calls. A practical way of doing so is to record conversations in the call centre only (and not in the break-room or on any common area telephone) and to have an enforced policy against placing or receiving personal phone calls while in the operations room. These steps will help to ensure that personal phone calls are not inadvertently recorded and that privacy rights are not encroached. Again, obtain legal counsel before recording any phone calls.

Source: Peter DeHaan Publishing Ltd, 2005
http://www.connectionsmagazine.com/articles/2/236.html