The 840AE was an updated variant of the CG840, offering upgraded page memory and a PS/2 keyboard connector instead of AT. Because Keywest Technology continued selling the 840AE after purchasing Video Data Systems, it could sometimes be seen bearing Keywest Technology branding.
As stated above, the 840AE used a PS/2 keyboard. The original keyboard was a standard 101-key IBM-style keyboard that had custom key markings on certain keys for various functions. To facilitate using a regular PS/2 PC keyboard, the mappings for these keys may be found here.