Abstract: A side entry sub logging system has features for removing the cable should the drill pipe become stuck. A release sub is connected between the drill pipe and the side entry sub. A mandrel is carried in the side entry sub and extends into the release sub. Logging cable which passes through the side entry sub sidewall passage also passes through a passage in the mandrel. The mandrel will move between upper and lower positions. The connection between the side entry and the release sub will release when contacted by the mandrel in the lower position. This enables the side entry sub to be pulled straight upward, bringing along with it the cable. A plug dropped into the drill pipe from the surface blocks the passage through the mandrel, enabling fluid pressure to be applied to push the mandrel downwardly to actuate the connection between the release sub and the side entry sub.