| 摘要 |
A direct access coupler for connecting a piece of terminal equipment, such as a modem to a telephone line pair, the coupler being of reduced size achieved in part by the use of a miniaturized isolation transformer and a constant current circuit to divert the off-hook current which would otherwise flow through the isolation transformer or a current-shunting choke and by the use of both an optical isolator off-hook circuit and an optical isolator ring detector circuit.
|
