Speech Processing Unit - Spu-S (Rex-Brd0017 Or Rofnb 157 16/3) - Nortel DCT1900 Technical Product Manual

4.4

Speech Processing Unit - SPU-S (REX-BRD0017 or ROFNB 157 16/3)

The SPU interfaces between a LTU/DTU and a CLU/SLU. Every SPU board contains eight Speech
Processing Channels (SPC, see Figure 4-2). Every SPC handles the speech processing for one
call. When a call is initiated, either by a Portable Telephone or by an incoming call, an SPC is
assigned to the call.
The main functions of the board are:
64 kbit/s PCM to 32 kbit/s ADPCM transcoding and vice versa
DTMF generation and dial tone detection
Echo control
System-DCT1900/R8/mw
© 2000-2005
Technical Product Manual - DCT1900
System Description, Radio Exchange Boards
SPC Peripheral
8 P8
BC
Peripheral
SPC
1 P1
Fig.4-2 SPU
4-3