Cassette Deck Cables and Connectors   

Most consumer grade cassette decks use phone plug connectors, also known as RCA connectors:   
The deck will be provided with two pairs of connectors, one pair for stereo input, the other for stereo output. 
The input connectors and cables can be connected to the left and right master output of the mixer.  The output of the cassette deck can be connected to the mixer via its monitor input or two of its input channels. 
Make sure that these input channels are either muted or their faders turned down when recording to avoid feedback.
cassette deck
cassette tape