B&B Electronics 232PTC9 Merkblatt
P#9156R1_232PTC9-0812 - 1/2
© 2003 by B&B Electronics. All rights reserved.
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PRODU
CT INFO
RMATI
O
N
B&B E
LECTR
ON
ICS
5
Ground
Control
Circuitry
3
TD
2
CTS
RTS
5
8
7
TD
RD
Port 1
3
RD
2
2
CTS
RTS
5-
8
7
Port 2
Master
Port
Port
RTS
7
3
TD
RD
Figure 2. 232PTC9 Port Diagram
Model: 232PTC9
RS-232 Two-Port Combiner
Introduction
B&B Electronics’ Model 232PTC9 permits two or more serial devices to share a serial port on a host computer. When
one of the devices on either of the slave ports transmits data, it captures the data path to the master port and locks out
the other slave port. When data transmission is finished, either slave port gets access to the master port by being the
first to start sending data. The RTS line can also be used to control data flow to the master port.
The 232PTC9 can be cascaded to combine as many devices as needed into one host port. A typical application would
be to share one host port with several terminals, scanners, scales, or other devices that only need access to the host
port occasionally as shown in Figure 1.
one of the devices on either of the slave ports transmits data, it captures the data path to the master port and locks out
the other slave port. When data transmission is finished, either slave port gets access to the master port by being the
first to start sending data. The RTS line can also be used to control data flow to the master port.
The 232PTC9 can be cascaded to combine as many devices as needed into one host port. A typical application would
be to share one host port with several terminals, scanners, scales, or other devices that only need access to the host
port occasionally as shown in Figure 1.
Operation
Data flow from master port to slave ports
All data that is sent to the TX line, pin 3 on the master port, is broadcast to both slave ports under all conditions. This
data appears on pin 2 of each slave port.
Data flow from slave ports to master port
data appears on pin 2 of each slave port.
Data flow from slave ports to master port
Data that is sent to the TX line (pin 3) on the slave ports must compete for the path to the master port. There are two
methods of capturing the path to the master port, RTS and automatic data sensing. The first slave port to either raise
its RTS line or transmit data captures the path to the master port. The path will be locked on that slave port until it either
lowers its RTS line, or 60 milliseconds after the end of its transmission. Note that the 232PTC does not buffer any data,
any data sent to the opposite slave port during this period will be lost.
methods of capturing the path to the master port, RTS and automatic data sensing. The first slave port to either raise
its RTS line or transmit data captures the path to the master port. The path will be locked on that slave port until it either
lowers its RTS line, or 60 milliseconds after the end of its transmission. Note that the 232PTC does not buffer any data,
any data sent to the opposite slave port during this period will be lost.
232PTC9
Bar Code
Port 2
Slave
Terminal
Port 1
Scanner
Master
Port
Port
Host
Computer
Slave
Figure 1. Application Example