1

LTC1344A

Software-Selectable

Cable Terminator

Daisy-Chained Control Outputs

DTE or DCE Multiprotocol Serial Interface with DB-25 Connector

D2

D1

LTC1544

RTS

DTR

DSR

DCD

CTS

D3

R2

R1

R4

R3

D2

LTC1543

LL

TXD

SCTE

TXC

RXC

RXD

2

14

24

11

15

12

17

9

3

1

4

19

20

623

22

5

13

8

10

18

7

16

1344A TA01

LTC1344A

D3

R2

R1

R3

D1

DB-25 CONNECTOR

D4

s

Data Networking

s

CSU and DSU

s

Data Routers

, LTC and LT are registered trademarks of Linear Technology Corporation.

FEATURES

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Software-Selectable Cable Termination for:

RS232 (V.28)

RS423 (V.10)

RS422 (V.11)

RS485

RS449

EIA530

EIA530-A

V.35

V.36

X.21

s

Outputs Won’t Load the Line with Power Off

The LTC

multiprotocol cable terminators. Each terminator can be

configured as an RS422 (V.11) 100

Ω minimum differen-

tial load, V.35 T-network load or an open circuit for use

with RS232 (V.28) or RS423 (V.10) transceivers that

provide their own termination. When combined with the

LTC1543 and LTC1544, the LTC1344A forms a complete

software-selectable multiprotocol serial port. A data bus

latch feature allows sharing of the select lines between

multiple interface ports.

The LTC1344A is similar to the LTC1344 except for a

difference in the Mode Selection table.

The LTC1344A is available in a 24-lead SSOP.