Abstract: A dual-purpose RCA plug structure includes: a base connecting a housing; the base is a hollow cylinder having an end being extended therein with a coaxial needle core having thereover an insulation envelopment, and having another end connecting with a wire connecting seat being grounded, the structure is characterized in that: the needle core has on its end an outer thread for movable connecting of a guide post having on its end a screw hole, the diameter of the guide post is larger than that of the needle core. Thereby, the plug has two functions: when the needle core of the small diameter connects the socket having a small hole, characteristic impedance of 75 ? can surely be obtained to maintain signal transmission without distortion; when the needle core of the small diameter is connected with the guide post with a large diameter, it can afford inserting connection of a conventional socket with a large hole.

Abstract: A digital signal-input/output socket structure comprises a guide post, a housing and two insulation sleeves. One end of the guide post connects a signal line, the other end allows insertion of a core post of an RCA plug of 75 ? (ohm). A grounding piece is extended over the outer periphery the housing; the grounding piece is connected with the housing using a fixing nut. Two ends of the two coaxial insulation sleeves contacting with each other cooperatively form an annular groove; the guide post has peripherally thereof a protruding annular flange for engaging with and being positioned in the annular groove. The structure suits electric connection of digital and video signal lines etc. of an audio and video unit; it can make the characteristic impedances of the signal lines on the two ends of the socket and the plug match with each other after connecting of the socket with the plug, thereby signals can be accurately transmitted.

Abstract: A structure of digital transmission line having a core material, a middle material layer and a coating layer. The core material is a transmission medium enveloped with an insulation PE foam layer. The coating layer includes at least one layer and is made of polyvinyl chloride. The middle material layer is provided between the core material and the coating layer, and is characterized by that the middle material layer is comprised of a copper foil wrapping layer, at least a metallic-wire knitting layer and a foamed Telfon-tape wrapping layer (PTFE). The middle material layer can get 100% obscuring, can minimize the degree of mutual interference, can maintain the characteristic impedance at 75&OHgr;, and can get the result that no refraction or reflection of transmitted signals is induced during transmission.

Abstract: A structure of signal transmission line has a core portion, a middle material layer and a coating layer. The core portion includes at least one transmission medium enveloped with an insulation layer. The coating layer includes at least one layer. The middle material layer is provided between the core portion and the coating layer, and has at least a metallic-wire knitting layer and a paper wrapping layer.

Abstract: A structure of digital transmission line comprising a core material, a middle material layer and a coating layer, whereof, the core material is a transmission medium enveloped with an insulation PE foam layer; the coating layer includes at least one layer and is made of polyvinyl chloride; the middle material layer is provided between the core material and the coating layer, and is characterized by that the middle material layer is comprised of a copper foil wrapping layer, at least a metallic-wire knitting layer and a foamed Teflon-tape wrapping layer (PTFE). The middle material layer can get 100% obscuring, can minimize the degree of mutual interference, can maintain the characteristic impedance at 75&OHgr;, and can get the result that no refraction or reflection of transmitted signals is induced during transmission.

Abstract: A structure of signal transmission line comprising a core portion, a middle material layer and a coating layer, it is characterized by that: the core portion includes at least one transmission medium enveloped with an insulation layer; the coating layer includes at least one layer; the middle material layer is provided between the core portion and the coating layer, and is comprised of at least a metallic-wire knitting layer and a paper wrapping layer. By separated transmitting of signals of high and low frequencies with the core portion with plural cores, the skin effect is lowered; and by providing more than one obscuring layers, the degree of mutual interference among a magnetic field, radio frequencies and static electricity can be lowered, and thereby, transmission with lower attenuation rate, smaller distortion and superior quality can be obtained.