18
W&T RS232 Serial Buffer
Modes
In standard mode (S1.8 = „off“) the RS232 Serial Buffer func-
tions like a data buffer using a FIFO principle. The data leave
the buffer on the output in exactly the same order as they were
written to the buffer by the computer. Pressing the „copy“ key
in this mode causes the entire buffer contents to be output
again, whereas „reset“ clears the buffer contents.
In block mode (S1.8 = „on“) the computer can write as many
data blocks as desired to the buffer, which the buffer then ad-
ministers as separate print/plot jobs. The buffer recognizes the
end of a data block from a pause in the transmission of at least
15 seconds. Each individual job can be output as often as de-
sired by pressing the „copy“ key. The „next block“ key activates
output of the next stored job. After outputting one data block,
the buffer stops outputting until the „copy“ or the „next block“
key is pressed. The „reset“ function clears the buffer contents
in this mode as well.
Pin assign ents and buffer connection
The input of the buffer is implemented as a 25-pin SUB-D
socket using DTE, so that as a rule the printer/plotter cable al-
ready present between the computer and buffer can be used.
The buffer output uses a 2m long serial cable with a 25-pin
SUB-D male using DCE at its end, which in most cases can be
plugged directly in to the peripheral.
In a very few cases it may be necessary to jumper pins 5 and 6
inside the 25-pin SUB-D male connector. An example for con-
necting the buffer to a 9- and 25-pin PC and to a plotter is
shown in the illustration below:
