Centronics 306 Technical Manual page 13

PARALLEL INPUT (TIMING)
M.,k - Binlty , - +2.410 !!U:; Vo!U
5p";l _ Bln.ty Q - 0 10
+
0.4 '0'011
O.'I~~
'~':'Sl ~ ~ ,
"st"lo'
O I . I S . ' O b l - U - - - - - - U -
.t
I-ISImlnl1
5oo1-151 m .. J
~--l....:.-+-"""
RS 232 SERIAL INPUT (TIMING)
Blud A.'I - tOO - 9600
5'1" Puille - On. Bit Timl
StOP Puille - min. of ani Bit Tlml
M"k - Binlty , _ -3 to ·21 Voln
SPiel - Bin.,y 0 - +3 to +21 Voln
Figure 1-2. BASIC BLOCK DIAGRAM
Paper movement is initiated by a line feed, vertical tab and form
feed function. In the standard 306 printer, vertical form movement is soft-
ware controlled by means of line count pulses, rather than hardware-controlled.
However, an optional vertical format unit, (VFU) is available for
hardware-controlled vertical formatting, identical to the Series 100 printers.
In addition, the printer recognizes the following special control
codes: bell, delete and elongated character, as described in Section 1.3.3.
1.3 PRINTER OPERATION
Basically, all printer functions can be grouped into one of the
following three categories: 1) character printing, 2) paper movement, and
3) other auxiliary functions such as bell, delete, etc.
1.3.1 CHARACTER PRINTING (Figures 1-3, 1-4)
A small aluminum carriage supports the print head assembly. During
printing operation, the carriage travels along the print line from left to
right. Printing is accomplished by selectively firing the print wires as
the print head moves from left to right across the print line. Printing
impulses energize the print solenoids and drive the print wires against the
ribbon, paper and platen to form the characters in a dot matrix pattern.
When the solenoids are de-energized, the wires are withdrawn so they are
flush with the surface of the jewel. Each solenoid can fire independently
up to five times for anyone character. Figure 1-3 shows an example of the
dot matrix forming the letter H. All character formation in the 5 x 7 and
9 x 7 dot matrix are shown in Series 300 Operators Manual.
1-3
Rev. F