Dell AT102W different power ratings

[Donut]

Hi,

I've noticed that the labels on different Dell AT102W (and presumably AT101W too) keyboards show several current ratings.

I have a keyboard labelled P/N 2425C REV A01, S/N M9808-22xxx which is rated 60mA. But I've seen pictures of other AT102W keyboards rated 75mA and 275mA. Is there any difference between the variants, other than power consumption? Maybe the manufacturer used different makes of microcontroller? Or could the 275mA boards have diodes for N-key rollover?

Assuming 9808 is a date code, my keyboard was made in month 8 1998. Some newer AT102W keyboards are rated 75mA (e.g. one on eBay is Dell P/N 093GDJ, S/N M0002045285, FCC ID GYUM90S).
This one on eBay is 75mA, S/N M9910046401
Another eBay picture is 275mA, P/N 95250 REV A01, S/N  M9706-41172
Another one pictured on the internet is P/N 95250, S/N M9603-014663, 275mA.
Another couple of pics I found show:
P/N ???? REV A01, S/N M9910046401, 75mA
P/N: 95250 REV A01, S/N: N9706-41511, 275mA

[fohat.digs]

the AT101 that I have handy says 275MA

It was made in Malaysia in 94

[Donut]

I received a black AT102W the other day. It seems to be a late model: straight cable, purple PS/2 connector, Euro symbol on 4 key. Made in Malaysia, rated 75mA.

The style of the labels on it is the same as shown in this eBay AT101W auction which was mentioned in another thread recently.

I wonder when the last AT101W/AT102W keyboards were produced. Maybe there is a production date code encoded in the serial number somehow???

[ideus]

I received a black AT102W the other day. It seems to be a late model: straight cable, purple PS/2 connector, Euro symbol on 4 key. Made in Malaysia, rated 75mA.

The style of the labels on it is the same as shown in this eBay AT101W auction which was mentioned in another thread recently.

I wonder when the last AT101W/AT102W keyboards were produced. Maybe there is a production date code encoded in the serial number somehow???

Why is the power consumption so important for you?

[Donut]

It isn't particularly, but could give an indication of how old a keyboard is if there isn't a manufacturing date code on the label. I did wonder whether the 275mA ones might have N-key rollover diodes, hence the higher power draw. But that probably isn't the case.

Assuming the keyboards do actually draw their rated current, an older 275mA one will use 1W more power than a later 75mA one. That could be a consideration if you're using a laptop, or a PS/2-to-USB converter connected to a USB hub which can't supply much power. You might find a newer keyboard would work there, but an older one wouldn't.