in telemarketing, failure to receive a call made to an inbound telephone center because the caller receives a busy signal. Blockage rates are usually expressed in terms of calls blocked as a percent of calls offered. Sophisticated telephone systems called switches can be used to place a prescribed number of callers on hold before producing busy signals. It is up to the telemarketer to manage the length of time spent on hold against the number of calls blocked. Most telemarketers strive to maintain a call blockage rate of less than 5% with no more than 25 seconds average hold time.

device used by telemarketers to dial a predetermined list of phone numbers and play a recorded message when calls are answered, without operator involvement. Automatic dialers can greatly increase the productivity of an outbound telephone operation. Unfortunately, the device cannot distinguish between playing the message to a child, an answering machine, a business, or a physician's office. Some automatic dialers do not disconnect until the message has ended, even if the called party hangs up. Concern about tying up phone lines has resulted in state and federal legislation restricting the use of automatic dialers. An automatic dialer may be an integral part of the telephone system or a stand-alone device.

type of automatic dialer that uses a pacing algorithm to adjust the timing of outbound telephone calls dialed, so as to deliver an answered call to every operator as soon as the operator becomes available. Timing is based on the number of operators on hand, the historical percentage of calls answered, and the average length of a call. If call lengths fall outside the expected range, operators may sit idle or calls may be lost, due to a shortage of available operators. Most telemarketers strive to maintain a no-op rate of less than 2%.

outbound telemarketing call initiated by an automatic dialing device that is not picked up by an operator immediately after the call is answered by a live party. Some no-ops are expected when using a predictive dialing system but should be kept at a volume below 5% of the calls answered. A no-op becomes an abandoned call if the called party hangs up before an operator gets on the line.