National Communications Page 3
PRODUCT DESCRIPTION
The SSU also allows for a primary audio feed, if connected, that will be
supplied to all speakers at all times.
ThisprimaryaudiofeedwillthenbereplacedbytheTDUmessage,only
ontheappropriatespeaker,whenevertheTDUistriggered.Theprimary
audio feed is then reconnected at the end of the TDU message.
Speakerscanbelocatedupto100mfromtheTDUunit,orgreaterthan100m
from the TDU if low resistance wiring is used.
The remote speakers connect to the SSU via a female 25 pin D type
connector. Each speaker has been allocated a specific pin position (see
page6).
Thisequipmentsupportsunpowered4ohmspeakersupto5wattsor8ohm
speakers up to 2.5 watts. Alternatively, powered speakers, or an external
amplifiercanbeusedforgreatervolumeoutput.
Power for the SSU and communication between the SSU and the TDU is
achievedviaasupplied6wiretelephonecable,whichconnectstoanRJ11
format 6 position communications port.
The SSU has 2 identical communications ports that provide for power and
communicationbetween theSSU, theTDU andother TDUaccessories, in
aDAISYCHAINfashion.
Itdoesnotmatterwhichofthe identicalcommunicationsportsareusedfor
input or output. A single 6 wire telephone cable is supplied with all TDU
accessories. There is no need for any other external connections.
TheSPEAKER SWITCHINGUNIT (SSU)accessory is availablein 3separate
configurations :
SSU-4 - 4 Speaker output unit for the Talking Display Unit
SSU-8 - 8 Speaker output unit for the Talking Display Unit
SSU-12 - 12 Speaker output unit for the Talking Display Unit