I/O Channel Physical Components Description - IBM 1 Series Manual

I/O Channel Physical Components Description
2-70 GA34-0033
Refer to Figures 2-30 and 2-31 for the following description. The card
sockets in a board are designated alphabetically from A (excluding I and
QO) starting at the left side of the board, viewed from the card side. Pin
rows on the top socket of a card slot are designated B on the left and D
on the right. The pins on the second socket are designated G onthe left
and J on the right. The pins on the third socket are designated M on the
left and P on the right. The pins on the bottom socket are designated S on
the left and U on the right. Each row of pins is numbered 2-13, top to
bottom. Note that the contact assignments on the card are shown as
viewed when facing the end of the card.
The center-to-center distance between card slots is 15.88 mm (0.625 in).
The dimensions of a standard IBM card are 178 mm by 229 mm (7 in by
9 in). The clearance on the wiring side (left side as viewed from the front
of the card file) is 5.6 mm (0.220 in), measured from the center of the
card stock, and clearance on the component side is 10 mm (0.380 in),
measured from the center of the card stock.
The maximum current that a device may draw through any single board
pin is 3 amperes. Additionally, the maximum wattage perslot is 19 watts,
total. Care must be taken to ensure that the power requirements for a new
device are compared with the total power requirements for the particular
system configuration. This ensures that the total power consumption
remains below the maximum ratings for the power supply.
I/O channel cables are available in 0.61-m (2-ft) or 1.83-m (6-ft) lengths.
They are 20-signal, unshielded cables with IBM connectors. Each
connector contains three ground pins: D0O8, B06, and B11. There is no
connection to pin DO3 (see Figure 2-29).