S0 Interface Module
digital Link
digital Link
PCX
UAI Board
(or MIX Board)
Digital set
to Mains
(Option)
S0 set
S0 Bus
S0 Terminal
Figure 4.18: Example of Configuration with an S0 Interface Module
The  S0  module  provides  an  S0  bus  supplying  power.  An  external  power  supply  (230V  AC/48V  DC
adapter) is required.
There are two possible operating modes on the S0 bus:
• Non  permanent  layer:  layer  1  must  be  set  up  by  the  calling  end  (PCX  or  terminal)  at  the  start  of
each call; layer 1 is shut down at the end of the call
• Permanent layer: operation of the S0 bus depends on the direction in which the initial call was set
up:
• If the call was set up from the PCX to the terminal, layer 1 is kept when the call ends.
• If the call was set up from the terminal to the PCX, layer 1 is shut down at the end of the call. It
must be  set  up  again  for the following  call.  If  operation  is incompatible with  the  terminal  used,
there are two possible solutions: Either layer 2 is kept, this prevents layer 1 being shut down, or,
layer 1 is  set up from the PCX  by making a call to  the terminal. The call does  not need to get
through.
4.12.1.2 Compliant Standards
4.12.1.2.1 Safety Requirements
• EN60950: European requirements
• UL 1950: US requirements
• CAN/CSA-C22.2 No 950-95: Canada
4.12.1.2.2 ECM
• EN55022: Limits  and  methods  of measurement  of  radio  interference characteristics of  information
technology equipment
• EN55024:  Limits  and  methods  of  measurement  of  immunity  characteristics  of  information
technology equipment
• FCC part15: US requirements
Chapter 
4
Installation and Cabling
3EH21123USAA - Ed. 01  - April 2017 - Installation Manual 118/207