TITLE
    Null Modem and Modem Eliminator: Pinouts
Article ID:
Created:
Modified: 		2671
3/22/88
10/27/98
TOPIC

    Below are pinouts for Null Modem, Null Modem with Handshake and Modem Eliminator using DB-25 signal pinouts.

DISCUSSION

    Null Modem
    From
    To
    1
    1
    2
    3
    3
    2
    4,5
    8
    6
    20
    7
    7
    20
    6
    8
    4,5
    Null Modem
    w/handshake
    From
    To
    1
    1
    2
    3
    3
    2
    4
    5
    5
    4
    6
    8,20
    7
    7
    8,20
    6
    Modem Eliminator
    From
    To
    1
    1
    2
    3
    3
    2
    7
    7
    4,5
    NC
    6,8,20
    NC

    Reference:

    RS232 Signal
    1 - Sig Gnd . . . . . . . . . . Normally Shield or Chassis Ground
    2 - TXD . . . . . . . . . . . . . Transmit Data
    3 - RXD . . . . . . . . . . . . . Receive Data
    4 - RTS . . . . . . . . . . . . . Request to Send
    5 - CTS . . . . . . . . . . . . . Clear to Send
    6 - DSR . . . . . . . . . . . . . Data Set Ready
    7 - GND . . . . . . . . . . . . . SIGNAL Ground
    8 - DCD . . . . . . . . . . . . . Data Carrier Detect
    20 - DTR . . . . . . . . . . . . Data Terminal Ready

    Note: Ring Indicate (RI) is not used or needed in computer-to-computer (DTE to DTE) direct connect configurations.

Document Information
Product Area: Computers; Peripherals
Category: Cables
Sub Category: Serial
Keywords: cabinfo

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