-This is a top-of-the-line MFJ 1272BYV TNC/Microphone Switch. It is compatible with KPC-3 and KPC-2 brands and is perfect for other radio communication accessories, parts, and accessories. The switch type is TNC/MIC and is a must-have for serious radio communication enthusiasts.  It is made to work with any compatible radio i.e. ICOM, Yeasu, and Kenwood specifically listed on the bottom.

The MFJ-1272BYV TNC/MIC Interface switch is a device that allows you to connect both your microphone and your TNC to the radio simultaneously. The device is designed to be used with any radio that has a standard, round, 8-pin microphone connector.

MFJ-1272BYV works with: KAM® VHF port, KPC-2, KPC-3.  See photo for radio compatibility. 
Includes:
MFJ-5084YH Cable (see photo for pinout)
MFJ-5080YV Cable (see photo for pinout)

On line manual. 
Microsoft Word - 1272B_9D.DOC (packet-radio.net) 
Page one has:

MFJ-1272B microphone switches were designed to be used with any radio that has a standard, round, 8-pin microphone connector. Because many TNCs have different connectors, MFJ offers 5 models: 
MFJ Model Number TNC and Multimodes 
 MFJ-1272B All MFJ TNCs, TAPR TNC II clones, and PK 12/96/900 
 MFJ-1272BX PK-232 
 MFJ-1272BYV KAM® VHF port, KPC-2, KPC-3
 MFJ-1272BYH KAM HF port MFJ-1272BZ PK-88