can handle multiple lines and connect to a computer so that a producer can follow who is on which line, communicate with the host, and manage the order of taking calls. Telephone hybrids are also used to interface production intercom systems to the PSTN. Related equipment POTS codecs, ISDN codecs, and IP codecs are used for remote broadcasts when it is possible to have specialized equipment at both ends of the connection. POTS codecs work with analog lines, ISDN codecs with ISDN lines, and IP codecs with any link that can provide IP connectivity. These employ audio data compression and decompression at each end. Audio bandwidths up to 20 kHz can be achieved this way. Compression is often via MPEG MP3 or AAC. Autopatches are telephone hybrids used by amateur radio operators to interface their radio equipment with telephone lines. See also Adaptive feedback cancellation Remote pickup unit References External links ITU-T Recommendations: Series G Modelling Telephone hybrids as 2 x 2 matrices Broadcast engineering Telephony equipment