Chapter 3

 

 

Hardware

 

 

 

 

 

 

Pin #

Pin #

Signal

Description

 

 

DB9

 

 

 

16

8

CTS2*

Clear To Send 2 – Indicates external serial communications device is

 

 

 

 

ready to receive data. Used as hardware handshake with RTS2 for low

 

 

 

 

level flow control.

 

 

 

RX2+

RX2+ – If in RS485 or RS422 mode, this pin is Receive Data 2 -.

 

17

4

DTR2*

Data Terminal Ready 2 – Indicates Serial port 2 is powered, initialized,

 

 

 

 

and ready. Used as hardware handshake with DSR2 for overall readiness

 

 

 

 

to communicate.

 

18

9

NC

Not Connected (Ring Indicator 2)

 

 

 

 

 

 

19

5

GND

Ground

 

20

NC

NC

Not connected

Notes: The shaded area denotes power or ground. Signals are listed in the following order RS232 and RS485/RS422.

Table 3-15. Serial B Interface Pin/Signal Descriptions (J13)

Pin #

Pin #

Signal

Description

 

DB9

 

 

1

1

DCD3*

Data Carrier Detect 3 – Indicates external serial communications device

 

(COM3)

 

is detecting a carrier signal (i.e., a communication channel is currently

 

 

 

open). In direct connect environments, this input will be driven by DTR3

 

 

 

as part of the DTR/DSR handshake.

2

6

DSR3*

Data Set Ready 3 – Indicates external serial communications device is

 

 

 

powered, initialized, and ready. Used as hardware handshake with DTR3

 

 

 

for overall readiness to communicate.

3

2

RXD3

Receive Data 3 – Serial port 3 receive data in

 

 

RX3-

RX3- – If in RS485 or RS422 mode, this pin is Receive Data 3 -.

 

 

 

 

4

7

RTS3*

Request To Send 3 – Indicates Serial port 3 is ready to transmit data.

 

 

 

Used as hardware handshake with CTS3 for low level flow control.

 

 

TX3+

TX3+ – If in RS485 or RS422 mode, this pin is Transmit Data 3 +.

 

 

 

 

5

3

TXD3

Transmit Data 3 – Serial port 3 transmit data out

 

 

TX3-

TX3- – If in RS485 or RS422 mode, this pin is Transmit Data 3 -.

 

 

 

 

6

8

CTS3*

Clear To Send 3 – Indicates external serial communications device is

 

 

 

ready to receive data. Used as hardware handshake with RTS3 for low

 

 

 

level flow control.

 

 

RX3+

RX3+ – If in RS485 or RS422 mode, this pin is Receive Data 3 -.

 

 

 

 

7

4

DTR3*

Data Terminal Ready 3 – Indicates Serial port 3 is powered, initialized,

 

 

 

and ready. Used as hardware handshake with DSR3 for overall readiness

 

 

 

to communicate.

8

9

RI3*

Ring Indicator 3 – Indicates external serial communications device is

 

 

 

detecting a ring condition. Used by software to initiate operations to

 

 

 

answer and open the communications channel.

9

5

GND

Ground

 

 

 

 

10

NC

KEY/

Key

 

 

NC

Not connected

LittleBoard 550

Reference Manual

45

Page 51
Image 51
Ampro Corporation Littleboard 550 manual CTS2, DTR2, DCD3, DSR3, RXD3, RTS3, TXD3, CTS3, DTR3