General

The subrack is a rack-wide compartment that contains hardware units. It is used for the MX-ONE Classic media gateway. The MX-ONE Classic with the MGU only has one subrack. The upper subrack, A, contained Mitel ASU Lite, ASU or Mitel ASU-II or Mitel ASU-III processor board. It also contained one or two sets of device boards that each was controlled by a Distributed Switch Unit (DSU).

The lower subrack, B, contained one or two sets of device boards that each was controlled by a DSU. Each subrack was powered by a DC/DC unit, which was located at the far right in each subrack. For more information, see installation instructions for HARDWARE INSTALLATION section INSTALLING MX-ONE CLASSIC.

If the lower subrack is to be replaced the processor in the upper subrack could remain in operation but for reasons of personal safety it is recommended that both subracks are powered down when any subrack needs to be replaced.

Always start by doing a proper shutdown of the Mitel ASU Lite, ASU or Mitel ASU-II or Mitel ASU-III server board. See Execution.