.2    Provide a means to ensure communication integrity.

        .3    To prevent damage to the system each data highway line shall be provided with a means of isolation, either
               optically or by some other means.

        .4    Upon failure of the network to communicate information from one SAP to other SAPs, retain the last
               legitimate value of each point in the SAPs that require it, and continue to control the systems based on those
               values. Failure of any SAP , or any part of a SAP on the network, shall not affect the ability of the network to
               communicate among the remaining SAPs.

        .5    Each physical or virtual point shall have a user-definable, unique, system-wide logical point mnemonic. The
               format of this point mnemonic shall conform to BCBC Point Naming Convention. All point functions such as
               commands, overrides, trends, reports, logs and graphics shall only need to use this unique logical point
               mnemonic.

.2    Terminal Unit Controllers (TUCs)

        For systems which include terminal unit controllers (TUC's).

       .1    TUC's shall be considered to be any panel connected to a sub-communication network, where access to the
               features and points of the TUC is only obtainable through the SAP to which the sub-network is connected.
               TUCs shall have a limited number of inputs and outputs, which are specifically designed to control one
               component serving a single thermostatic zone (e.g., VAV terminal unit, dual-duct terminal unit, fan-coil unit,
               zone heat pump, etc.).