6
4. (optional) Plug the CoCo keyboard into the pass-
through connector on top of the interface. Ensure that
the conductive strips on the mylar film line up with the
pins on the connector. By using the passthrough,
both PC and CoCo keyboards can be used at the
same time.
5. Plug in the AT keyboard into the DIN connector on the
interface board. Route the cable to exit out the
cartridge port.
6. The red alligator clip goes to +5V. On a CoCo III this
is most readily available on a large resistor which
stands away from the circuit board (R19, far left side
of the circuit board; connect to the pin nearest the
front of the CoCo).
7. The black alligator goes to ground. The metal RF
shield near the joystick connectors on the CoCo Ill's
circuit board. If you're not sure, ask someone who
knows as a mistake here could damage the interface
and/or the CoCo!
8. The white wire alligator clip connects to the CoCo's
reset button. On the CoCo 3, the rightmost pin on the
top of the reset button is where the clip should go.
9. Close the cover and replace the screws that were
removed in Step #1. Watch the screw lengths. Route
the AT keyboard cable out along the front right side of
the CoCo.
7
Operation
Key maps
If you take a close look at both a CoCo and AT keyboard,
you will soon realize that there is a distinct difference in the
layout of non-alphabetic keys. Because of this, the interface
supports two different modes of operation: PC key map and
CoCo key map. The two modes can be toggled between
using the SCROLL LOCK key. When the SCROLL LOCK LED is
off, the interface is in PC key map; when it is on, CoCo key
map is in effect. In PC key map, the interface maps the keys
based what is printed on the AT keyboard's keycaps. For
example, pressing SHIFT 2will generate the @ character.
When in CoCo key map, pressing the same keys will
generate the " character. The CoCo key map maintains a
one-to-one correspondence of PC keys with CoCo keys
based partly on their physical layout. This is useful for
games which depend on the CoCo's layout of keys, or for
users who can't quite teach their fingers a different key
layout.
Num Lock
The NUMLOCK key toggles the state of the corresponding
keyboard LED, and changes the behavior of the keypad
keys. When the NUMLOCK LED is on, the keypad keys
behave the same as the keys "0"-"9" and ".". When NUMLOCK
is off, the keypad keys behave the same as the arrow keys
and macro keys to the keypad's immediate left.
Caps Lock
In PC key map mode, pressing the CAPSLOCK key toggles the
keyboard's caps lock state. While the keyboard's caps lock is
on, the interface will automatically press SHIFT Whenever an
alphabetic character is typed. Note that this doesn't affect
the computer's caps lock state. Press SHIFT CAPSLOCK
