9 line termination unit -ltu – Nortel Networks DCT1900 User Manual
Page 47
Technical Product Manual - DCT1900
System Description, Radio Exchange Boards
System-DCT1900/R8/mw
4-9
© 2000-2005
4.9
Line Termination Unit - LTU (REX-BRD0007 or ROFNB 157 02/6)
LTU2 (REX-BRD0019A or ROFNB 157 25/2)
LTUs are used only in Standalone configurations. The LTU provides the analog interface between
the PBX and the RE. Every LTU board contains 8 Line Termination Circuits (LTC, see Figure 4-8).
An LTC interfaces to the PBX through a two–wire analog subscriber line. Every analog line is
dedicated to a specific Portable Telephone number. The LTC terminates the line to the PBX like an
ordinary wired analog telephone.
The main tasks of the LTU board are:
z
To establish physical connection between the PBX and RE
z
On/Off hook detection
z
Ring signal detection
z
R–button function handling
z
Pulse dialing (not currently supported)
z
Analog to digital speech processing [PCM (Pulse Code Modulation)] and vice versa
Fig. 4-8 LTU
Peripheral
P8
Peripheral
P1
LTC
8
BC
LTC
1
Analog
Telephone
Line
Analog
Telephone
Line