An initiation block for connecting a detonator with a detonating cord has a body that includes opposing first and second faces and a first and a second chamber extending between the opposing faces. The first chamber is formed by a first bore serially arranged with a second bore, which is shaped to seat the detonator adjacent to the second face. The second chamber is parallel with the first chamber and shaped complementary to the detonating cord. A passage provides communication between the first chamber and the second chamber. A booster is positioned in the first bore, proximate to the first face, and along the passage. The body further has an opening that provides communication between an exterior of the body and a portion of the chamber between the booster and the detonator.