The Bristol-based 41-year-old, who played with Robins boss Paul Buckle at Exeter City, took his first training session on Friday morning and has signed an initial deal until the end of the season.
Edwards won Wales caps during his playing career, which saw him on the books of Carlisle United, Bristol City, Preston North End, Blackpool and finally Exeter, where he had a player-coach role. He played alongside current Robins skipper Matt Taylor at the Devon club.
He went on to become assistant manager at St James Park before taking his first managerial role at Tranmere in May of this year, but he lost his job after a poor start to the season which included a 3-2 home defeat by Cheltenham.