Abstract: A compressed gas system including a source of gas under pressure and a pair of delivery lines communicated at one pair of corresponding inlet ends with the source and provided with structure at the other pair of discharge ends for sealed attachment with fittings opening into a communication cable at points spaced therealong on opposite sides of a predetermined location in the cable in which a poured plug is to be formed is provided. A bypass line equipped with a double T bypass valve is connected in parallel between the delivery lines and a gas flow line equipped with an in-line gas flow indicator is also connected in parallel between the delivery lines. The gas flow line is provided with a shut-off valve and each of the delivery lines is equipped with a gas flow control valve and a gas pressure gauge downstream from the associated gas flow control valve.