Rs-232 signals – Rockwell Automation 2706-DXX Dataliner Message Display DL5 Series User Manual

Page 48

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2706-UM001A-US-P

6-2

Using the Serial Port

RS-232 Signals

The DL5’s RS-232 port uses Transmit Data signal, Receive Data signal, and
Signal Common. The Clear To Send, Data Carrier Detect, and Data Set
Ready pins are tied high (+12V) by the DL5, allowing direct connection of
the DL5 to terminals or computers requiring a request to send signal. No
jumpers at the terminal or computer connector should be required.

Data Carrier Detect - Pin 1 Indicates that a continuous frequency
“capable of being modulated or impressed with a signal” is being received.
The DL5 sets this line high.

Transmit Data - Pin 2 Sends out the serialized data from the DL5 (e.g., the
serial data is on this pin).

Received Data - Pin 3 This signal also carries serial data. However, the
serialized data is sent from another device as input to the DL5.

Data Terminal Ready - Pin 4 Indicates the transmission device (terminal)
is connected, powered up, and ready to send data. The DL5 ignores this line.

Signal Common - Pin 5 The ground reference for all other signals.

Data Set Ready - Pin 6 Indicates that a communications device is
connected, powered up, and ready for data transmission. The DL5 sets this
line high.

Request to Send - Pin 7 Signal from the terminal device requesting the
communication device to send data. This typically turns on the data carrier.
The DL5 ignores this line.

Clear to Send - Pin 8 This signal indicates to the transmitting device that it
can start sending data. The DL5 sets this line high.

Ring Indicator - Pin 9 This signal indicates that each device is physically
connected to adjacent devices. The DL5 sets this line high.

Pin Number

Signal Name (Signal Mnemonic)

Signal Type

1

Data Carrier (DCD)

Output

2

Transmit (TXD)

Output

3

Receive Data (RXD)

Input

4

Data Terminal Ready (DTR)

Input

5

Signal Common (COM)

--

6

Data Set Ready (DSR)

Output

7

Request to Send (RTS)

Input

8

Clear to Send (CTS)

Output

9

Ring Indicator (RI)

Output

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