Telephone Line Extenders (Comrex, Gentner)
The STC in Washington, DC, possesses equipment that can improve the quality of a standard dial-up telephone circuit (also known as POTS—"Plain Old Telephone Service"). This equipment uses one, two, or three separate dial-up circuits to encode and decode audio. It is a less expensive alternative than equalized audio circuits and microwave links, but it is also of lesser quality. Telephone extenders perform acceptably for speech, but not for music. | 
