feature between the Bell and Independent practice,
the Bell Companies adhering to the horizontal and vertical arrangement,
while the Independent Companies have employed the vertical arrangement
on both sides. We are informed that in the future the new smaller
installations of the Bell Companies will be made largely with the
vertical arrangement on both sides. At the left of Fig. 421 is shown the
relay rack in two sections of two bays each. This illustration also
gives a good idea of the common practice in disposing of the cables
between the frames in iron runways just below the ceiling of the
terminal room.

_Types of Line Circuits._ The design of the terminal-room floor plan
will depend largely on the arrangement of apparatus in the subscribers'
line circuits with respect to the distributing frames and relay racks.
The Bell practice in this respect has already been referred to and is
illustrated in Fig. 348. In this the line and cut-off relays are
permanently associated with the answering jacks and lamps, resulting in
the answering-jack equipment being subject to change with respect to the
multiple and the line through the jumpers of the intermediate frame. The
practice of the Kellogg Company, on the other hand, has been illustrated
in Fig. 353, and in this the line and cut-off relays are permanently
associated with the multiple and with the line, only the answering jacks
and lamps being subject to change through the jumper wires on the
intermediate frame. This latter arrangement has led to a very desirable
parallel arrangement of the two distributing frames and the relay rack.
These are made of equal length so as to correspond bay for bay, and are
placed side by side with only enough space between them for the passage
of workmen--the relay rack lying between the main and intermediate
frames. In this scheme all the multiple and answering-jack cables run
from the intermediate distributing frame, and the cabling between the
intermediate frame and the relay rack and between the relay rack and the
main frame is run straight across from one rack to the other. This
results in a great saving of cable within the terminal room, over that
arrangement wherein the cabling from one frame to another is necessarily
led along the length of the frame to its end and then passes through a
single runway to the end of the other frame.

=Large Manual Offices.= For purposes of illustrating the practice in
housing the apparatus in very larg