Experienced Egypt international joined Town on a two year deal after leaving Bristol City.
He started his career with boyhood club Brighton and Hove Albion, making 300 appearances for The Seagulls in an 11 year stay.
El-Abd was voted Brighton's Player of the Year in 2011 as they were promoted to the Championship.
He moved to Bristol City in January 2014 for an undisclosed fee.
However, he struggled to make an impact at Ashton Gate, making only 16 appearances before enjoying loan spells with Bury, Swindon and Gillingham at the back end of last season.
Still only 31, El-Abd adds experience and aggression to the Town backline.