3A COMMTEK CO., LTD have greatest experience and technique in manufacturing any kind of RS-232, RS-485, RS-422, CURRENT LOOP, USB, X.21, V.35, RS-449 with signal power interface converter series, Protocol analyzer, Data scope, LAN cable tester, Breakout box, Special cable. We also design and manufacture new models / products according to buyer's request. Your any requirement is welcome. We not only provide competitive prices, excellent quality and also helps customers to solve technical problems, improve quality, reduce extra costs, and assist customers to become more competitive. Welcome OEM / ODM partners for cooperation. We provide all product series to all over the world since 1985, especially in Europe, USA and ASIA. The countries are France, Germany, Italy, Spain, The Netherlan...