User guide

94 RealCT Direct API Developer Guide
Chapter 4: E1 Networking
Organizing the E1 Data
Organizing Data into E1 Frames
The E1 line carries data from 30 data channels plus two
channels for framing and signaling over two pairs of wires. At
the transmitting end, a multiplexer receives a 64 Kb/s signal
from each the 30 lines. It interleaves 8 bits of data from each
data channel plus signaling and framing information into a
single serial stream of data. The process of interleaving data
from each data channel is called time division multiplexing
(TDM).
Figure 18 shows data entering a multiplexer and being
transmitted on the line. The multiplexer at the far end
separates the data into the original 30 data channels plus
signaling and framing information.
Figure 18. An E1 Line
A multiplexer at the remote end reassembles the multiplexed
data into 30 individual data channels plus signaling and
framing information.
Multiplexer
2.048 Mb/s
Multiplexer
Line 0 (64 Kb/s)
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Line 29 (64 Kb/s)
Line 0 (64 Kb/s)
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Line 29 (64 Kb/s)