Output Baud Rate - HP 7470A Interfacing And Programming Manual

Additional Connector Pin Allocations
Pin No. RS-232-C
CCITT V.24
Function/ Signal Level
17
20
14*
16*
AA
CA
DD
CD
SBA
SBB
101
105
115
108.2
118
119
Protective ground
Request To Send from the
plotter
Always High = ON = "O"
2 +12 V
External Clock Input
High = ON = +2.4 V to
+5 V
Low = OFF =00 V to
+0.4 V
Data Terminal Ready to
modem
High = ON = "O"
'=~+12 V
Low = OFF = "1"
E -12 V
Secondary Transmit Data
Data line from plotter to
terminal
Secondary Received Data
Data line to plotter from
terminal
*Used to establish monitor mode with special Y-cable(Part No. 17455A).
Output Baud Rate
The plotter is designed to operate in an asynchronous mode with
switch-selectable baud rates of 75, 110, 150, 200, 300, 600, 1200, 2400,
4800, and 9600. See the 7470A Operator's Manual for instructions on
setting the baud rate. However, setting all BAUD switches to zero and
connecting an external clock input to pin 17 of the connector allows
operation of the plotter at any intermediate baud rate up to 9600baud.
Both the receiver (RRC) and transmitter (TRC) clocks will operate at
the same clock rate. Requirements for the clock signal are as follows:
1. The clock frequency must be 16 times the desired baud rate.
2. The baud rate must not exceed 9600.
3. The duty cycle of the clock pulse should be close to 50%.
10-12 RS-232-C/CCITT V.24INTERFACING