The old T43 style keyboard connectors don’t work anymore.
I found those candidates (I’ve to check them first but they’re available)
CONN PLUG 0.5MM 40POS SMD
Found generic name: WR-40P-VF-N1-ND
Those look like good candidates:
WR-40P-VF-N1 same as the x220/x230 keyboard
Datasheet picture: http://jae-connector.com/en/pdf/SJ100338.pdf
WR-40S-VF-N1 same as the x220/x230 motherboard
Datasheet picture: http://jae-connector.com/en/pdf/SJ100337.pdf
This Chinese-English-Spanish web page has nice photos of the connectors:
UPDATE: The WR-40P-VF-N1 and WR-40S-VF-N1 look very similar to the ones Lenovo is using but they’re not the same. The pin spacing is correct but the connector doesn’t fit. Those WR connectors are not as long the one on the keyboard. Now I have no idea which connector does it use because this seemed like a good candidate.
The X220 keyboard has those part numbers written below:
Parts NO: 0B35709
FRU NO: 04W2753
It might be usefull later that it also says: DC 5v / 25mA max
Parts NO: 45N2106
FRU NO: 45N2141
I also received another barely used keyboard from Israel. It looks the same as the previous one but this Kósher keyboard 😉 requires less energy. DC 5V /7.0mA
Update: The keyboard itself will consume the same since it doesn’t have any chips on it but the trackpoint does so I guess they’ve a different trackpoint version but the wiring is the same and I feel them the same way.
Other laptos also have the same keyboard numbers:
IBM/Lenovo Thinkpad T410, T410i, T410S, T410Si, T510, W510 …