PIN ASSIGNMENTS

DB-9 Port Pin Assignments

EIA

CCITT

Description

Switch’s

PC DB9

Modem

Signal

Circuit

Signal

 

DB9 DTE

DTE

DB25

Direction

 

 

 

Pin #

Pin #

DCE Pin #

DTE-DCE

CF

109

DCD (Data Carrier Detected)

1

1

8

<------

BB

104

RxD (Received Data)

2

2

3

<------

BA

103

TxD (Transmitted Data)

3

3

2

------>

CD

108.2

DTR (Data Terminal Ready)

4

4

20

------>

AB

102

SG (Signal Ground)

5

5

7

-------

CC

107

DSR (Data Set Ready)

6

6

6

<------

CA

105

RTS (Request-to-Send)

7

7

4

------>

CB

106

CTS (Clear-to-Send)

8

8

5

<------

CE

125

RI (Ring Indicator)

9

9

22

<------

Console Port to 9-Pin COM Port on PC

Switch’s 9-Pin

 

CCITT Signal

 

PC’s 9-Pin

 

Serial Port

 

 

 

COM Port

 

 

 

 

 

 

1

DCD

-----------

DCD ------------

1

2

RXD

<---------

TXD ------------

3

3

TXD

-----------

RXD ----------

>

2

4

DTR

-----------

DSR ----------

>

6

5

SGND

-----------

SGND ----------

5

6

DSR

-----------

DTR ------------

4

7

RTS

-----------

CTS -----------

>

8

8

CTS

<---------

RTS -------------

7

9

RI

-----------

RI ---------------

9

Console Port to 25-Pin DCE Port on Modem

Switch’s 9-Pin

 

CCITT Signal

 

Modem’s 25-Pin

Serial Port

 

 

 

DCE Port

 

 

 

 

 

1

<

--------- DCD ------------

8

2

<

--------- RXD ------------

3

3

-----------

TXD ----------

>

2

4

-----------

DTR ----------

>

20

5

-----------

SGND ----------

7

6

<

--------- DSR ------------

6

7

-----------

RTS -----------

>

4

8

<

--------- CTS -------------

5

9

<

--------- RI ---------------

22

B-2

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Image 162
SMC Networks SMC6924VF manual DB-9 Port Pin Assignments, Console Port to 9-Pin COM Port on PC