Abstract: A method and apparatus for aligning a digital communication data stream across a cell network, wherein plurality of timeslot samples are generated by sampling the digital communication data stream transferred over a first circuit-switching communication link. The timeslot samples are assembled into a series of communication cells in a bit or byte skewed arrangement. An align flag in the header of a communication cell indicates that the communication cell contains an aligned timeslot sample.

Abstract: An improved chimney stack of the type having at least one flue through which gases flow and an outer shell for establishing an insulating space surrounding the flue wherein the present improvement includes heat exchanger means secured to the flue and having first and second ports with the first port extending through the outer shell and communicating with the outside air and with the second port communicating with the insulating space surrounding the flue and wherein the heat exchanger means admits and heats outside air and discharges heated outside air into the insulating space surrounding the flue during cool down of the chimney stack whereby minimization of condensation of flue gasses during cool down of the chimney stack is achieved.