can everyone tell me is it authentic IBM keyboard or mixed?

[youxiaojie]

Can every one tell me is it authentic IBM keyboard? Or is it the possible of assembled /mixed by different parts?I see the parts of connexion (opposite to the screw side) is not so fit.loose.and the manufacturer date of upper down case half year before manufacturer. please help me. And the connexion line ,ps to sdl, is flat not round of 1391401.

[AJM]

I'm not a Model M expert, but the case of my one Model M (1995) doesn't fit perfectly either, although a bit better than yours. Maybe someone already tried to open it from that side (because he didn't have the right tool for the screws).
What I can tell from my experience with Model Fs is, that an older manufacturing date of the cases compared to the rest is perfectly normal.

[E TwentyNine]

The flat cable SDL connector was common on IBM POS keyboards, and the flat cable hardwire was also common on later M's.

I don't know that I've seen a flat cable SDL/PS2 on a M, but it might have gotten switched in the field.

I'm not seeing anything there that would lead me to believe anything wasn't authentic.

[youxiaojie]

Thanks you mean the PS SDL wire is OK and the keyboards is OK but they are not a pair. The pair of model m is round wire no matter which factory the KB was made, Lexmark IBM and unicomp.
Thanks

[Snowdog993]

Thanks you mean the PS SDL wire is OK and the keyboards is OK but they are not a pair. The pair of model m is round wire no matter which factory the KB was made, Lexmark IBM and unicomp.
Thanks

I think E29 is saying that the "Point Of Sale" IBM keyboards were sold with flat cables. I tend to agree with him. The SDL cable, although being "flat" works just the same as one that is "round". You can get a round SDL cable if you prefer, but I don't think it will make any difference.
And yes, there were FLAT cables produced for IBM keyboards at that time. It's not uncommon. The round ones last much longer because the flat cables split and fall apart over time.