A call transfer is a telecommunications mechanism that enables a user to relocate an existing telephone call to another phone or attendant console, using a transfer button or a switchhook flash and dialing the required location. The transferred call is either announced or unannounced.

If the transferred call is announced, the desired party/extension is notified of the impending transfer. This is typically done by putting the caller on hold and dialing the desired party/extension; they are then notified and, if they choose to accept the call, it is transferred over to them. Other terms commonly used for an announced transfer include "attended", "consult", "full-consult", "supervised" and "conference" transfer.

On the other hand, an unannounced transfer is self-explanatory: it is transferred without notifying the desired party/extension of the impending call. It is simply transferred to their line by way of a "transfer" key on the operator's phone or by keying in a string of digits which achieves the same function. Other terms commonly used for an unannounced transfer include "unsupervised" and "blind". Unsupervised call transfer can be either warm or cold - depending on moment when B-leg is disconnected. See also Call forwarding