Audio processor for communications transmitter. Used in my ham radio station to improve audio intelligility for contest use. It is a bit of an overkill but I used it to learn lots about equalisation and speech compression. Uses LA3600 equaliser plus SSM2167 speech compressor. (My first surface mount component with 0.5 mm pin pitch, learned lots about reflow soldering with a hot air gun). Also has a recorder chip ISD 1760 to make CQ Contest calls. Balanced transformer on the output to minisise audio loop noise problems. Multiple connectors to accomodate different microphones, avaition headset, PC mic and Yaesu 9 pin mic. Housed in Hammond diecast box.