| 摘要 |
<p>PURPOSE:To attain economization by securing data transmission and reception even if a main and a terminal equipment side has a shift in clock phase, and then removing two transformers which are necessary in phantom feeding without reference to a phantom feeding system. CONSTITUTION:In a main equipmentI, transistors TrQ1 and TrQ2 are connected in series, the TrQ1 is connected to a power source while the TrQ2 is grounded, and a connection point between the Trs Q1 and Q2 is connected to the power source through a high resistance; and a TR circuit which changes in state at the connection point (m) corresponding to the on-off states of the Trs Q1 and Q2, a signal receiving circuit for detecting a signal voltage, and a terminal connected to the connection point (m) and the input point of the signal receiving circuit are provided. A terminal equipment II, on the other hand, has a signal receiving circuit for detecting a signal voltage, a TrQ3 turned on and off corresponding to data to be sent out, a stabilized power source circuit PS for supplying a stabilized voltage, and a terminal connecting with the input point of the signal receiving circuit, the output point of the TrQ3, and the input point of the circuit PS. Further, the main equipmentIand terminal equipment II are connected mutually by a data transmission line DL.</p> |
