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COMMUNICATION LINE BUFFERS
The Bit Buffer Unit Module
The bit buffer unit contains from one to ten buffer channels and one control section for that
module.
The control section contains a basic timing unit and common circuitry. The buffer
control section contains hardware that is common to all the bit buffer channels in the unit module.
Each bit buffer channel is capable of receiving and transmitting digital data. A bit buffer unit
module may terminate from one to ten full duplex, half duplex, or simplex transmission lines
which are all operating at
the~
bit rate.
CONTROL
SECTION
1
BIT BUFFER MODULE
BIT BUFFER CHANNELS
2
3
5
7
8
9
10
....
_
Figure 11. Bit Buff er Module
BBC
(------------
REC'V
XMIT
THE BIT BUFFER CHANNEL The Bit Buffer Channel (BBC) buffers one bit of information at a
time between the DATANET-30 and the communication line.
It
is used on communication lines
operating with stop-start asynchronous format (e.g., normal Teletype) and either 5, 6, 7 or 8
level codes.
Each bit buffer channel in a module is assigned a buffer selector address by the address plug for
that module.
The address applies to both the receive and the transmit section. The address for
the bit buffers in a module can be whatever is desired for the system and they need not be
sequential.
Thus a bit buffer channel may be added to a module and given an address without
disturbing the existing address arrangement.
System considerations limit operating speed of the bit buffer lines to the standard Teletype rates
of 45, 50, 56.25, 66.2, 72.6, 75, 110, and 150 bits per second. The rate is established per module
with a timing connector plug.
The selected bit rate will apply to all the bit buffer channels
physically located in a module.
If
more than one bit rate is used in a system, the different bit
rate lines would be terminated in separate bit buffer unit modules using a timing connector plug
set for the bit rate of that module.
[ID/A\Ll&\~~11~ ~®------------
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