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can be printed out and corrected. The supervisor can send service messages to open or
close out stations and/ or to send data to intercept storage.
12.
Format Conversion--Changing the order of spacing of data from the incoming order to the
desired outgoing order.
13.
Error Control--A variety of error detection and correction schemes can be used. Oper-
ator error codes can be recognized and a recovery or re-start procedure set up for that
message.
The DATANET-30 can be programmed to control the format of a message and
notify the operator of any format errors. Also, transmission errors can be recognized
through echoplex retransmission.
Parity check of codes and block parity checks can be
used.
14.
Alternate Routing of Messages--Supervisory changes in routing on a temporary basis in
case of line or terminal outage. Programmed automatic alternate routing is also possible.
15.
Priority Messages--Messages may contain a "Priority Level Code" that can be recog-
nized by the DATANET-30 program.
Thus hot messages or data can be handled before
routine administrative messages.
Operation
The operation of the switching center is fully automatic--under control of the program. The
sequence of transmission of terminals on a multipoint private line is also controlled by the pro-
gram.
Each message contains a destination code--the name or number of the remote station
or stations where the message is going. After a message is received from a remote station, the
program interrogates the destination code of the message in memory, then transmits it to the
proper remote terminals.
The DATANET-30 is programmed to handle all normal messages in
accordance with a standard format and standard routing codes for the system. A standard
incoming message format would be used for all incoming traffic, including rush messages, normal
messages, and service or control messages.
The distinction between messages is made by the
mnemonic address code.
The system is capable of operation with only occasional manual intervention and control. The con-
trol is accomplished through the supervisory terminal to open and close stations by time of day
and enter other control messages. When a station is closed, the program forwards all messages
for the closed station to intercept storage.
The supervisory terminal normally consists of a keyboard/printer Teletype unit. This terminal
is used as a message intercept position for incorrectly routed or formatted messages. The super-
visor looks at the messages and decides what action is necessary, such as, correct the heading
and re-enter the message, ask for retransmission, etc.
The terminal is also used to notify the
supervisor of line malfunctions and for printing out periodic status reports on the switching
center operation.
The detailed operation of each system will be developed according to individual system require-
ments, such as; routing, service and control codes, format, number of lines and remote terminals,
and the many other overall system operational requirements.
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