The fully electronically programmable complex filter employs a network of current amplifiers, each CA having differential pairs biased with different tail currents, the outputs being programmed by adjusting these tail currents. In this manner, it is unnecessary to have a new process of dry etching to form a through-hole electrode after thinning the wafer and equipment development. The present invention also provides a method for implementing multimedia ring back tone service. The user can then use the digital rocker switch to adjust the audio gain for the selected program. The selected portion of the circuit is replicated and delay logic is inserted to delay the inputs into the replicated portion of the circuit. A selected one of the frequencies of the locating signal is indicated to the locator using a frequency code that is produced by a locating signal frequency control arrangement which forms part of the transmitter, which frequency code can individually identify each of the frequencies.