PI 4D/35: keyboard connector variations?

[Hakimoto]

hey all,

just recently i wondered... aren't 4D/35s supposed to have D9 keyboard connectors that are Indigo compatible? My PI has a normal DIN connector, the Indigo 1 keyboard cable plugs right in and works a charm.

Were there different revisions of that aspect of the machine?

TIA

[jan-jaap]

The 4D/20 and 4D/25 have a DB9 style connector like the PowerSeries
The 4D/30 and 4D/35 have a min-DIN like the Indigo(1)

It's just a matter of connector; all 4D-style keyboards are electrically the same (unlike the PS/2 keyboards on later models).

[robespierre]

This is a pretty old thread, but there doesn't seem to be a more recent one on this topic.

There are more differences than just the connector: the power supplied by the keyboard port is also different.
Personal Iris 4D/20-25 is like Power Series, it provides +12V, -12V to the keyboard, and the keyboard provides +5V,-5V to the mouse. 4D/30-35, Indigo, and Onyx provide only +8V to the keyboard. (a pin is assigned to -8V but it is not connected.) Keyboard passes +8V through to the mouse. So the mice are also different electrically.

I have a 4D/25-compatible keyboard that I was able to connect to a 4D/35 by custom cable. It works somewhat but some keys strike intermittently, but that is probably a problem with the key matrix itself. The keyboard has a cheap feel unlike the Indigo keyboards which feel very nice.
(Because it works on only +8V and I also looked inside, the DE-9 type keyboard uses only the positive power pin. There is a ICL7660 inside that converts regulated +5V to -5V, to power the keyboard signal drivers and also feed power to the mouse.)

In "This Old 4D" page, a modification is described for certain Sun M4 optical mice to convert them to SGI mice. This would only be for the Professional Series and 4D/20-25 type, since the mouse needs +5V and -5V supplied. There are a lot more unused traces in the mouse, so it may be possible to adapt it to +8V power, but the circuit doesn't appear compatible with ICL7660.

[jan-jaap]

The 4D/20 and 4D/25 have a DB9 style connector like the PowerSeries

This is plain wrong: the PowerSeries have a DB15 connector.

There are more differences than just the connector: the power supplied by the keyboard port is also different.
Personal Iris 4D/20-25 is like Power Series, it provides +12V, -12V to the keyboard, and the keyboard provides +5V,-5V to the mouse. 4D/30-35, Indigo, and Onyx provide only +8V to the keyboard. (a pin is assigned to -8V but it is not connected.) Keyboard passes +8V through to the mouse. So the mice are also different electrically.

all 4D-style keyboards are electrically the same

'compatible' would have been more accurate. Mea culpa

Making your own DB9 <-> miniDIN6 or DB15 <-> miniDIN6 cable is straightforward, but they also existed as genuine SGI parts. You will not fry an Indigo keyboard/mouse (the 8V model) if you use it with an older system (which supplies +/- 12V).

I usually use an Indigo keyboard / mouse set with all my older 4D systems, mostly because I don't like the optical mice. Or, actually: I can't stand the sensation of their cold, metal mouse pads against my wrist.

[robespierre]

Yes, they should be compatible. (although I don't know whether the oldest type of 4D keyboard can run on positive power only.)

An important point that doesn't get mentioned much is that the mice are different and only compatible with their respective keyboards, due to the different location of the power regulators.

[jan-jaap]

I don't know whether the oldest type of 4D keyboard can run on positive power only[

Me neither. I only tried the other way around.