I work for company that use to install US stuff and installed a lot of the Assention 2000s. It is my understanding US never manufactured a telescopic jack. If we couldn't do a in-ground or couldn't get the rise out of their twin post single stages we ended up having to go with their roped hydraulic units.

This is not to say US may have bought a telescopic jack from someone else and integrated it into one of their packages.

Do you have a pic of the jack? It would help identifying it.