The normal condition of a telegraph loop is closed; that is, there is
current in the loop even though patch cords are removed. The path of
current through C of figure 10 of CCTM 105-50-6, extract is from "T"
T1, and R to R1.
R, and T1 to R1.
R1, and R to T1.
TN, and R to RN.
Assume that you wish to listen to signals passing through transmit and
receive patch circuits shown in figure 1-5 of CCTM 105-50-6, extract.
Using a headset equipped with a double-plug patch cord, you will NOT
hear signals when you patch the plug into either the
transmit LINE or the receive EQUIP.
transmit EQUIPMENT or the receive LINE.
transmit LINE or the transmit MON.
receive EQUIP or the receive MON.
concept shows that the jacks are wired to achieve the function of
make one, break one.
make two, break two.
The WECO VF patch bays are made up with jack details M and N.
detail is primarily used for miscellaneous type circuits such as
spare line circuits, test equipment and speakers.
spare line circuits, test equipment and DC circuits.