<HTML ><HEAD ><TITLE >Cable from console port to modem</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="Remote Serial Console HOWTO" HREF="index.html"><LINK REL="UP" TITLE="Serial cabling" HREF="serial.html"><LINK REL="PREVIOUS" TITLE="Jargon" HREF="serial-jargon.html"><LINK REL="NEXT" TITLE="Cable from console port to terminal (or another PC)" HREF="serial-pc-terminal.html"></HEAD ><BODY CLASS="SECTION" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >Remote Serial Console HOWTO</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="serial-jargon.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 11. Serial cabling</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="serial-pc-terminal.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECTION" ><H1 CLASS="SECTION" ><A NAME="SERIAL-PC-MODEM" ></A >11.2. Cable from console port to modem</H1 ><P >The <SPAN CLASS="ACRONYM" >RS-232</SPAN > standard defines the interconnection of computers and modems, so there is little to go wrong here by simply purchasing a pre-assembled cable. There are two types of cable: cables with connectors for a standard 25-pin D connector on the computer; and cables with connectors for a proprietary 9-pin D connector used on the <SPAN CLASS="ACRONYM" >IBM</SPAN > <SPAN CLASS="PRODUCTNAME" ><SPAN CLASS="ACRONYM" >PC/AT</SPAN ></SPAN > and many other computers. The cables have titles like <I CLASS="CITETITLE" ><SPAN CLASS="ACRONYM" >RS-232</SPAN > 25-pin computer (<SPAN CLASS="ACRONYM" >DTE</SPAN >) to 25-pin modem (<SPAN CLASS="ACRONYM" >DCE</SPAN >)</I > or <I CLASS="CITETITLE" ><SPAN CLASS="ACRONYM" >RS-232</SPAN > 9-pin <SPAN CLASS="ACRONYM" >IBM</SPAN > <SPAN CLASS="PRODUCTNAME" ><SPAN CLASS="ACRONYM" >PC/AT</SPAN ></SPAN > computer (<SPAN CLASS="ACRONYM" >DTE</SPAN >) to 25-pin modem (<SPAN CLASS="ACRONYM" >DCE</SPAN >)</I >. Most modems are packaged with a suitable cable.</P ><P >If you need to manufacture your own cables, see the <I CLASS="CITETITLE" >Serial-HOWTO</I > for the <SPAN CLASS="ACRONYM" >RS-232</SPAN > pinout for your computer. Connect Transmit Data on the computer to Transmit Data on the modem, Receive Data on the computer to Receive Data on the modem, and so on for Signal Ground, Clear to Send, Ready to Send, Data Set Ready, Data Terminal Ready and Data Carrier Detect.</P ><P >For professional computer room installations consider routing the serial cable through an <SPAN CLASS="ACRONYM" >RJ-45</SPAN > patch panel. There are two common pinouts on used on the <SPAN CLASS="ACRONYM" >RJ-45</SPAN > connector: <A HREF="http://yost.com/Computers/RJ45-serial/" TARGET="_top" >Yost</A > and <A HREF="http://www.cisco.com/warp/public/701/14.html" TARGET="_top" >Cisco 2500-series</A >.</P ><P >If you create your own pinout for unshielded twisted pair cable then be sure that your pinout twists a Signal Ground wire with the Transmit Data wire and another Signal Ground wire with the Receive Data wire. Although the <SPAN CLASS="ACRONYM" >RS-232</SPAN > signals are not balanced, this twist will result in the least amount of signal degradation and noise pickup.</P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="serial-jargon.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="serial-pc-terminal.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Jargon</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="serial.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Cable from console port to terminal (or another PC)</TD ></TR ></TABLE ></DIV ></BODY ></HTML >
