52
TERMINAL ELIMINATOR PLUS
5.5.4.O Protocol for Transmitting Slave Records
During either of the Concentrate modes, the master port’s output data stream
is a concentration of data from slave ports. When do we switch from one slave
port’s data to the next? On a character-by-character basis, a line-by-line basis,
a record-by-record basis, or on an inter-record gap (a user-assigned “no-
receive delay” timeout)? The Terminal Eliminator Plus gives you two options.
You can set a DIP-switch position to have the master port switch to another
slave’s data either (a) at the end of a record or (b) on an inter-record gap.
Using the first setting (switch after a record), when the TEP transmits the
end of one slave port’s record, it will search through its internal receive
buffers for data from the other slave ports (in sequential order), looking for a
complete record to transmit. When it finds one, it will then switch to the slave
port that sent that record. Note that if only one slave port is sending data, its
records will be transmitted one after the other until another slave port has a
complete record to transmit.
Using the second option (switching on an inter-record gap), when the TEP
transmits the end of a slave port’s record, it will continue to transmit any
additional records from this same slave port that are buffered or are being
received, until it finds an inter-record gap—inter-record gaps that occurred
between existing buffered records are remembered and treated as such—that
meets or exceeds the user-assigned time limit for this particular slave port.
After this timeout it will search through its internal receive buffers for data
from the other slave ports (in sequential order), looking for a complete
record to transmit. When it finds one, it will then switch to the slave port that
sent that record.
If the user has disabled a slave port’s “no receive” timeout, then the
Terminal Eliminator Plus, after transmitting the end of one of that slave
port’s records, will immediately begin looking to transmit a valid record from
another slave port.
Switching which slave is transmitting to the master device on an inter-
record gap is useful in applications where viewing multiple consecutive
records is more “user-friendly” than viewing single-record slices. This is the
case in applications concentrating console outputs from one or more
mainframes. The mainframe may send a paragraph of information instructing
the operator to mount a certain magtape so it can run the payroll program.
This paragraph of instructions is much easier to read if it isn’t interrupted by
records from other mainframes until the paragraph is completely displayed.
System switch SWG position 7:
ON:
Transmit one record from a slave port, then look for records
from subsequent ports to transmit
OFF:
Transmit records from one slave until the inter-record gap (“no
receive” timeout) occurs
