How to connect thunderbolt to non thunderbolt

Reverse problem than normal. One computer is in for hard drive repair. I need to access data stored on a G-Drive pro that only has thunderbolt ports – with a Mac that was pre-thunderbolt days. I’ve tried to access via thunderbolt to firewire but with no success. Not even sure if this is possible. Any suggestions? There are tons of things on connecting a new computer with older drive but I have a new drive that I need to connect to a older computer on at least a several week basis.

If the device has Thunderbolt ports it requires a computer with Thunderbolt. There is no way to adapt the other direction.