OPU-1
UNIVERSAL POWER-LINE CARRIER SYSTEM TYPE OPU-1
GENERAL DESCRIPTION - Rev 7 (May 2019)
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2.5.3
Asynchronous programmable modem type MFPU
The MFPU is an asynchronous narrowband modem with frequency-shift keying (FSK)
modulation for the transmission of data at speeds of 50 to 1200 Bd.
The technology used in the MFPU modem is based on digital signal processing and allows
the transmission speed and central frequency of each channel to be programmed by the
user. The transmission speed can be 50, 100, 200, 600 or 1200 Bd, whilst the central
frequency of each channel can be selected from between a wide range of values, including
those enumerated in recommendations R.35, R.37, R.38A and R.38B of the ITU-T. The
MFPU modem is also compatible with standard V.23 of the ITU-T.
2.5.4
Others
IOPU
BASEBAND INPUT/OUTPUT CIRCUIT
It contains two 600
balanced inputs and two 600
balanced outputs and
the whole-band service-telephony circuits.
It also receives the external input for power-boosting control, the external input
of the M wire (transmission call) and the signalling of the E wire (reception
call).
The type of module depends on whether the terminal is working with one or
two analog channels in this way:
IOPU.01
One analog channel (CH1).
IOPU.02
Two analog channels (CH1 and CH2).
This module is always installed adjacent to MOPU module.
FTPU
VFT-TRANSIT FILTER
Audio-frequency signal filter and amplifier with phase equalizer. It is used to
select a determinate band and to carry out the transit towards other
communication channels.
It includes a transformer-decoupled output with programmable level.
