SP503(2000) View Datasheet(PDF) - Signal Processing Technologies

Part Name

Description

Manufacturer

SP503
(Rev.:2000)

Application Note

Signal Processing Technologies 

DTE and DCE configurations

with the SP503

The SP503 has designated signals such as "Trans-

mit Data", "Clear-to-Send", etc.which design-

ers can easily allocate the appropriate SP503

transceivers for the corresponding signals. The

data signals specified in the EIA standards and

CCITT are referenced in the SP503 datasheet as

DTE. Some customers have wondered if they

can use the SP503 for DCE applications.

Although it can be confusing at first glance, the

DCE implementation is the mirror image of the

DTE side. For the DTE, TxD is a driver which

drives the data to RxD, a receiver, on the DCE

side. TxC or TT is a driver on the DTE side

which drives the clock signal to the RxC re-

ceiver on the DCE side.

The next three pages illustrate the CCITT signal

allocations from the SP503 in either DTE or

DCE to the DB-25 connector. As shown, it is

possible to use a DB-25 connector for the vari-

ous protocols offered by the SP503.

DB-25 Connector Pin Assignments for Various Protocols

DB-25 Pin # RS-232

EIA-530

1

shield

shield

2

TxD

TxD(A)

3

RxD

RxD(A)

4

RTS

RTS(A)

5

CTS

CTS(A)

6

DSR

DSR(A)

7

Signal GND Signal GND

8

DCD

RLSD(A)

9

–

RxC(B)

10

–

RLSD(B)

11

–

TxC(B-DTE)

12

DCD (2nd) TxCC(B-DCE)

13

CTS (2nd)

CTS(B)

14

TxD (2nd)

TxD(B)

15 TxCC (DCE) TxCC(A-DCE)

16

RxD (2nd)

RxD(B)

17

RxC

RxC(A)

18

LL

LL

19

RTS (2nd)

RTS(B)

20

DTR

DTR(A)

21

RL

RL

22

RI

DSR(B)

23

SRS

DTR(B)

24

TxC (DTE) TxC(A-DTE)

RS-449

RS-422

V.35

V.36

shield

shield CCITT# 101 CCITT# 101

SD(A)

T(A)

103(A)

103(A)

RD(A)

R(A)

104(A)

104(A)

RS(A)

C(A)

105

105(A)

CS(A)

–

106

106(A)

DM(A)

–

107

107(A)

Signal GND Signal GND 102

102

RR(A)

I(A)

109

109(A)

RT(B)

–

115(B)

115(B)

RR(B)

I(B)`

–

109(B)

TT(B)

–

113(B)

113(B)

ST(B)

S(B)

114(B)

114(B)

CS(B)

–

–

106(B)

SD(B)

T(B)

103(B)

103(B)

ST(A)

S(A)

114(B)

114(B)

RD(B)

R(B)

104(B)

104(B)

RT(A)

–

115(A)

115(A)

LL

–

–

141

RS(B)

C(B)

–

105(B)

TR(A)

–

–

–

RL

–

–

140

DM(B)

–

–

107(B)

TR(B)

–

–

–

TT(A)

–

113(A)

113(A)

SP503AN

SP503 Application Note

2

© Copyright 2000 Sipex Corporation

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