DOCS/vt102-ug/table6-8.html


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<DIV CLASS="navbar"><A HREF="http://vt100.net/"><IMG CLASS="button" SRC="vt100.net-logo.png" ALT="VT100.net" HEIGHT="16" WIDTH="102"></A> VT102 User Guide<TABLE WIDTH="100%">
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<TD ALIGN="LEFT"><A HREF="chapter6.html">Chapter 6</A></TD>
<TD ALIGN="CENTER"><A HREF="contents.html">Contents</A></TD>
<TD ALIGN="RIGHT">&nbsp;</TD>
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<TABLE ID="T6-8" CLASS="majortable" FRAME="VOID" RULES="GROUPS" CELLSPACING="0" CELLPADDING="4" BORDERCOLOR="#ffffff">
<CAPTION>Table 6-8 Half-Duplex with Supervisory Control (HDX A) Signals</CAPTION>
<THEAD>
<TR VALIGN="BOTTOM">
<TH>Pin</TH>
<TH>Name (Mnemonic)</TH>
<TH>CCITT&nbsp;/ EIA</TH>
<TH>Switch</TH>
<TH>Description</TH>
</TR>
</THEAD>
<TBODY>
<TR VALIGN="TOP">
<TD>1</TD>
<TD>Protective ground<BR>(PGND)</TD>
<TD>101/AA</TD>
<TD>-</TD>
<TD>Connects to terminal chassis. Also connects to external ground through third wire of
power cord.</TD>
</TR>
<TR VALIGN="TOP">
<TD>2</TD>
<TD>Transmit data<BR>(TXD)</TD>
<TD>103/BA</TD>
<TD>S6</TD>
<TD>From VT102:<BR>When switch S6 is on (closed), signals on TXD are serial characters
and breaks generated by the terminal. TXD is in mark state when no characters are
transmitted.</TD>
</TR>
<TR VALIGN="TOP">
<TD COLSPAN="5"><P CLASS="note">NOTE: When S6 is on (closed), switch S7 must be off (open).</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>3</TD>
<TD>Received data<BR>(RXD)</TD>
<TD>104/BB</TD>
<TD>-</TD>
<TD>To VT102:<BR>RXD receives serial characters from the computer.</TD>
</TR>
<TR VALIGN="TOP">
<TD>4</TD>
<TD>Request to send<BR>(RTS)</TD>
<TD>105/CA</TD>
<TD>S1</TD>
<TD>From VT102:<BR>When switch S1 is on (closed), RTS is on if terminal is ready to
transmit characters and off if terminal is receiving characters.</TD>
</TR>
<TR VALIGN="TOP">
<TD>5</TD>
<TD>Clear to send<BR>(CTS)</TD>
<TD>106/CB</TD>
<TD>S2</TD>
<TD>To VT102:<BR>When switch S2 is on (closed), CTS indicates when modem is ready to
transmit data to the computer. When on, modem is ready to transmit data and CTS indicator
is on. When off, modem is not ready to transmit data and CTS indicator is off.</TD>
</TR>
<TR VALIGN="TOP">
<TD COLSPAN="5"><P CLASS="note">NOTE: When S2 is on (closed), switch S3 must be off (open).</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>6</TD>
<TD>Data set ready<BR>(DSR)</TD>
<TD>107/CC</TD>
<TD>-</TD>
<TD>From VT102:<BR>When DSR is on:
<UL>
<LI>DSR indicator is on</LI>
<LI>Modem connects to a communication line</LI>
<LI>Modem is ready to use modem control signals.</LI>
</UL>
When DSR is off:
<UL>
<LI>DSR indicator is off</LI>
<LI>Terminal performs a disconnect.</LI>
</UL></TD>
</TR>
<TR VALIGN="TOP">
<TD>7</TD>
<TD>Signal ground<BR>(SGND)</TD>
<TD>102/AB</TD>
<TD>-</TD>
<TD>SGND is common ground reference potential for all connector signals except protective
ground. SGND connects to protective ground conductor.</TD>
</TR>
<TR VALIGN="TOP">
<TD>8</TD>
<TD>Receive line signal detector<BR>(RLSD)</TD>
<TD>109/CF</TD>
<TD>-</TD>
<TD>To VT102:<BR>Also called carrier detect, RLSD is on when communication line signals
are good enough to receive data from computer. When off, terminal is transmitting data
to computer or modem is disconnected from communication line; data received is ignored.</TD>
</TR>
<TR VALIGN="TOP">
<TD>12</TD>
<TD>Secondary receive line signal detector<BR>(SRLSD)</TD>
<TD>122/SCF</TD>
<TD>S4</TD>
<TD>To VT102:<BR>Also called secondary carrier detect, SRLSD is on when transmitting data
to computer. When off, terminal is receiving data from computer or modem is disconnected
from communication line.</TD>
</TR>
<TR VALIGN="TOP">
<TD>19</TD>
<TD>Secondary request to send<BR>(SRTS)</TD>
<TD>120/SCA</TD>
<TD>S8</TD>
<TD>From VT102:<BR>When switch S8 is on (closed), SRTS is on if terminal is ready to
receive characters and off if terminal is transmitting characters.</TD>
</TR>
<TR VALIGN="TOP">
<TD COLSPAN="5"><P CLASS="note">NOTE: Switch S5 must be off (open).</P></TD>
</TR>
<TR VALIGN="TOP">
<TD>20</TD>
<TD>Data terminal ready<BR>(DTR)</TD>
<TD>108.2/CD</TD>
<TD>-</TD>
<TD>From VT102:<BR>DTR is on when terminal is on-line and off when terminal is
off-line or performing a disconnect. When on, modem can usually answer calls
(modem auto answer option). When off, modem usually disconnects and does not
answer calls.</TD>
</TR>
<TR VALIGN="TOP">
<TD>23</TD>
<TD>Speed select<BR>(SPSD)</TD>
<TD>111/CH</TD>
<TD>S10</TD>
<TD>From VT102:<BR>SPSD is on when receive speed SET-UP feature selection is greater
than 600 baud. SPSD is off when speed is 600 baud or less.</TD>
</TR>
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<TD ALIGN="LEFT"><A HREF="chapter6.html">Chapter 6</A></TD>
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