The E1SC-UIM (User Interface Module) gathers the RS-232 asynchronous
serial data, the analogue voice channel and the alarm and control signals
together and converts them into a synchronous 64 kb/s digital data stream using
unique framing and error correction protocol. This data is then passed to the
E1SC-MM (Media converter and Multiplexer) module, which multiplexes the
service channels and the incoming E1 data onto a 2.5 Mb/s digital stream then
converts it to optical signals. At the opposite side the optical signals are
converted back to electrical, de-multiplexed and the data is passed to the
corresponding interfaces, that is E1 to the line interface and service channels to
the SC-UIM module. The SC-UIM module decodes the 64 kb/s digital data and
converts it back to RS-232 serial, analogue voice and low speed signaling.
More detailed information about the functional blocks inside the individual
modules can be seen on Figure 2. (E1SC-MM) and Figure 3. (SC-UIM) E1SC-
MM (Media converter and Multiplexer).
Figure 2. E1SC-MM Function Blocks
E1 line interface
The E1 line interface provides physical connection to the E1 network via
balanced 120 Ohm UTP or unbalanced 75 Ohm coaxial ports. It provides data
and clock recovery, AMI/HDB3 encoding and decoding, AIS and BPV
detection.
Master
CLK
CPLD
logic
E1 line
inter-
face
FO
transmitter
FO
receiver
PLL
circuits
SC-IF
J Tag
DIP
SW
Manage-
ment
interface
Front
panel
