Patch Panel Signal Hubs - IBM 360 Manual

Figure 9. Open Cover Plate
leftmost panels (called operational patch panels). Opera­
tional patch panel 1 is associated with counters 0-7;
operational patch panel 2 is associated with counters 8-15.
Both operational patch panels are functionally identical.
Signals from operational patch panel 1 can be intercon­
nected to operational patch panel 2. See "Appendix D" and
"Appendix E" for a detailed description of operational
patch panel 1, and operational patch panel 2.
The rightmost section o f the patch panel contains
additional logic and test functions used to check and
perform reliability test on the Basic Counter Unit. The
panel is divided into two sections: XLF (expanded logic
functions) and TEST. See "Appendix F" for a detailed
description of the XLF and TEST patch panel.
To the right of the test panel is a storage compartment
for patch panel wires. Wiring the patch panel is accom­
plished by connecting selected hub positions with patch
panel wires. For this purpose, fifty 4-inch patch panel wires
and twenty-five 8-inch patch panel wires are provided with
the Basic Counter Unit as standard accessories.
A patch panel image card is provided inside the cover
plate to be used by the operator as a reference wiring
diagram (Figure 26). Before wiring the patch panel, the user
should plan his work on the IBM Basic Counter Unit Patch
Panel Planning Form, ZX22-6952 (see "Appendix G").
IBM Internal Use Only

Patch Panel Signal Hubs

On the patch panel are 20 pairs of signal hubs designated
SGL 1-20 (Figure 26); each pair supplies a two-way
distribution of the same signal from each of 20 connected
monitor probes. The signals from the signal hubs provide
the basic input to other logic areas of the patch panel by
connecting the signal hubs to other logic hubs with patch
panel wires.
Patch Panel Signal Definition
Signals on the patch panel are either true or not true (false)
by following the Boolean algebra rules of true, false logic.
True is the functionally active state of an event; not true
is the functionally inactive state of an event.
CPU or I/O Device Signal Definitions
Signals to be measured in a CPU or I/O device exist as
either a minus (-) signal level or a plus (+) signal level. That
is, the electrical state of a signal in the CPU or I/O device
may be negative or positive when active.
Patch Panel Signal Hub Evolution
The evolution of a signal at a signal hub on the patch panels
begins when the monitor probe is connected to a pin
Operating the IBM Basic Counter Unit 11