AC drives that use ±5v instead of analog±10v?

I 've been looking at AC servo drives on ebay (low end of the price range) and found this particular drive is controlled by ±5v in Velocity mode instead of the ±10v analog I see on most drives. With my limited understanding of drives this seems to me to only go half speed however the drive/ motor combination is supposed to be good for full speed.
What gives here? This is a drive from 1990's. Will this work well at ±5v or is it too obsolete?

Its probably OK to drive these from a +- 10V interface, just set the output limit to 1/2 scale. If the drives are designed for +-5V
then 5V should give full velocity. Another option would be to take a +-10V interface and divide the voltage by 2 at the drive
( with 2 equal resistors)