Siemens EH.75M.11. Especificaciones descargar pdf (Pagina 278)

T400 Controller Facilities Manual

667/EB/20200/000 Page 25-7 Issue 9

4. S4 - 600 Ohm/High Impedance Switch

Switch S4 - Installation

(To be performed by qualified/authorised installation/service engineer.)

WARNING - THIS SWITCH IS LOCATED UNDER THE PCB COVER.

FOR UK USAGE THERE ARE NO USER ACCESSIBLE PARTS UNDER

THE COVER. BABT APPROVAL WILL BE INVALIDATED IF THE

COVER IS LEFT OFF OR MISSING.

This switch is always set to the 600 Ohms position for all Radial, Multi Point

and/or Multi Terminal lines. The switch is set to 600 Ohms during manufacture

and therefore does not need to be changed. Where British Telecom or other

telephone line supplier has agreed to provide Multi-drop circuits i.e. where

more than one OTU is to be connected to one line, the final OTU on the line is

set to 600 Ohm, all others on the line need to be set to high impedance. Then

the switch may be set as appropriate for the OTU, as noted below.

Note to Service / Installation engineers:-

This switch is located underneath the cover. The top half of the cover should

be removed in order to set the switch. No cabling should be connected at this

stage, but before removing the cover make sure that the cable connected to

socket SK1 of the PCB is not connected to the telephone network. Ensure the

cover is re-fitted correctly after setting the switch.

Make a note of the switch setting on the OTU installation sheet for future

reference.

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Siemens EH.75M.11. Especificaciones Pagina 278