I'll start by saying this should be simpler than how it actually works.
It's common to be facing trouble in two different counties. Let's say you get arrested for something in Fulton County, but you're on probation in Henry County. You bond out of Fulton's jail, but then a few months later you get arrested and brought to Henry County because your probation officer filed a petition to revoke your probation.
How can you get back to Fulton to face those charges? (By the way, facing charges and a probation revocation is a common situation where people get railroaded by not knowing their rights--I'll write about that later).
To get back to Fulton, a judge in Fulton must order the Fulton Sheriff to drive down to Henry and pick you up. Then, when court is finished, the Sheriff must drive you back to Henry. Usually you'll stay a night in Fulton's jail before and after the court date.
The important point is that Henry County does not have to bring you to Fulton! And if no court date is scheduled, you won't get transported over. This makes it very difficult to take care of minor charges without having a lawyer to arrange everything.