If it's within the same state prison system, there is little to no downtime for phone calls. If you were on his previous visitation list, you might have little downtime there too.
https://www.inmateaid.com/ask-the-inmate/after-an-inmate-gets-moved-from-one-unit-to-another-how-long-is-it-before#answer
Accepted Answer Date Created: May 17,2016