Juniper Systems Allegro DOS Manual - Manual (Page 44)

44 Allegro DOS Owner’s Manual
Communication Ports
The Allegro DOS has two 9 pin serial ports (located on the top of the
case).
These ports are recessed to protect them in case of a drop. They are
also completely sealed.
9 Pin Serial Communication Ports
The standard 9 pin serial communication ports (COM1 and COM2)
allow for the simultaneous operation of two serial devices such
as printers, modems, and bar code wands. Additional power is
provided on COM1 to power bar code wands and other sensors. The
data transfer rate on these ports ranges from 300 baud to 115 Kbaud.
Rubber connector protectors keep dirt and moisture out of the ports.
The ports are sealed without the protectors.
Be sure to use the serial communication cable (9 pin to 9 pin)
included with the Allegro to connect the Allegro to a desktop PC. A
wiring diagram of the cable is shown in Chapter 5, Technical Reference.
Note that a standard ‘straight through’ serial cable does not work.
9 Pin D Connector Pinouts
Pin #
1
Data Carrier Detect (DCD) Input
2 Receive Data (RCD) Input
3 Transmit Data (TXD) Output
4 Data Terminal Ready (DTR) Output
5 Ground (GND)
6 Data Set Ready (DSR) Input
7 Request To Send (RTS) Output
8 Clear To Send (CTS) Input
9 Ring Indicator (RI) Input
Connecting Sensors to COM1
Pin 4 (DTR) on COM1 supplies up to 200 mA at +5 volts to power
bar code scanners and other sensors. This signal (DTR) must be
set high by the application to take advantage of this feature. When
the DTR signal goes low, the output is -5 volts. Insure that the
device connected to the DTR line can accept negative voltages or is
protected against them (standard RS-232 signal levels).
▲