Figure 6-33.--Four wire banks and associated wipers shown in the normal position.

wipers to return to the normal position. The release

supervisory and control functions. When the wipers

springs are operated to release the external control

are stepped in the X direction, the X-off normal

circuitry. The release magnet restores when both the

springs are operated; when stepped in the Y direction,

X- and Y-off normal springs return to normal.

the Y-off normal springs are operated. Only 10 steps

are allowed in either direction. If these are exceeded,

THE WIRE BANK.-- The 42- by 10-wire bank

the overflow springs are operated. When the X-off

associated with the XY switch is actually made up of

normal or Y-off normal springs are operated, a path is

six smaller wire banks: four 10- by 10-wire banks and

competed to the release magnet. A ground (signal)

two 1- by 10-wire banks. The 10- by 10-wire banks

can then be extended to pin 29 of the XY switch plug

are used with the four wires associated with each

(fig. 6-30) to operate the release magnet, causing the

telephone line. These four wires are the tip (T) and

ring (R) for transmission, and sleeve (S) and helping

sleeve (HS) for supervisory and switching. The 1- and

10-wire banks (XX and X) are used to electrically

indicate the X position of the wipers when the wipers

are stepped in the X direction. Each of these banks is

associated with its own particular wiper on the XY

switch. The switch wipers are referred to as the T, R,

S, HS, and XX-X wipers or banks (fig. 6-31). Figure

6-32 is a simplified diagram of one of the 10- by

10-wire banks (as seen from above) and the associated

wiper.

This wire bank runs the length of the switchboard

and is associated with the same wiper in all the other

XY switches in the system (fig. 6-33). The X motion

of the switch locates the wiper at a position (or bank)

opposite the proper section of the wire bank referred

to as the level. The Y motion of the switch positions

the wiper into the bank to establish the connection at

the proper point. The switch then remains in position

Figure 6-32.--Wire bank and associated XY switch wiper

indefinitely until it is released. A terminal block at the

simplified schematic diagram.

end of the wire bank provides the necessary

Figure 6-33.--Four wire banks and associated wipers shown in the normal position.

6-37