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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><HTML><HEAD><TITLE>VT100.net: Digital VT100 User Guide</TITLE><LINK HREF="vt100-ug.css" TYPE="text/css" REL="stylesheet"><LINK HREF="/favicon.ico" TYPE="image/x-icon" REL="shortcut icon"></HEAD><BODY><DIV CLASS="navbar"><A HREF="http://vt100.net/"><IMG CLASS="button" SRC="vt100.net-logo.png" ALT="VT100.net" HEIGHT="16" WIDTH="102"></A> VT100 User Guide<TABLE WIDTH="100%"><COL SPAN="3" WIDTH="33%"><TBODY><TR><TD ALIGN="LEFT"><A HREF="chapter1.html">Chapter 1</A></TD><TD ALIGN="CENTER"><A HREF="contents.html">Contents</A></TD><TD ALIGN="RIGHT"><A HREF="chapter3.html">Chapter 3</A></TD></TR></TBODY></TABLE><HR></DIV><H1 ID="S2">Chapter 2<BR>Installation, Interface Information and Specifications</H1><H2 ID="S2.1">Installation</H2><H3 ID="S2.1.1">Site Considerations</H3><P>The design of the VT100 terminal (<A HREF="figure2-1.html">Figure 2-1</A>) will normally pose few constraintson selecting a place in which to install the terminal. In most cases, any environmentsuitable to the terminal operator will be a satisfactory environment in whichto operate the terminal. Extremes of temperature and humidity should be avoided.A summary of VT100 guaranteed operating conditions is found at the end of thissection.</P><H3 ID="S2.1.2">Unpacking and Maintenance</H3><P>The VT100 shipping carton contains the following items:</P><UL><LI>VT100 monitor</LI><LI>VT100 detached keyboard</LI><LI>VT100 power cord</LI><LI>VT100 SET-UP label</LI><LI>VT100 User's Guide</LI></UL><P>To install the VT100 perform the following steps:</P><OL><LI>Remove the VT100 from the shipping carton and place it in the desiredwork area.</LI><LI>Place the keyboard in front of the terminal and plug the keyboard coiledcord into the keyboard receptacle located on the rear of the terminal(<A HREF="figure2-2.html">Figure 2-2</A>).</LI><LI>Verify that the power selector switch shows the correct wall outletvoltage (115 V is standard in the U.S.) and the power switch is off.</LI><LI>Connect the power cord to the power cord receptacle on the rear of theterminal and plug the other end of the power cord into a nearby walloutlet.</LI><LI>Connect the communications cable to the appropriate communicationsreceptacle.</LI><LI>Turn the power switch on. The terminal will now automatically performthe power-up self-test and either the ON LINE or LOCAL light locatedon the keyboard will be turned on. After approximately one minute thecursor will be visible in the upper-left corner of the screen. If any otherindication is shown, refer to Part 5 of the operator information chapter.</LI><LI>Set the desired SET-UP features as outlined in the operator's section ofthis manual.</LI><LI>Once the installation setup procedure is complete, record the SET-UPfeatures selected on the VT100 SET-UP label and attach the label tothe underside of the keyboard.</LI></OL><H3 ID="S2.1.3">User Maintenance</H3><P>The keyboard keys are the only moving parts of the terminal and require no preventivemaintenance by the owner. The VT100 surfaces may be cleaned with soapand water or any mild detergent. Cleaners with solvents should not be used.</P><P>The VT100 packaging is not meant to be weatherproof; there are several openingsin the case through which liquids, coins, paper clips, and other objects can fall.Such objects would disturb the electronic operation of the terminal if they cameinto contact with the circuitry. For this reason, avoid putting drinks and metalobjects on the top of the terminal, or using excessive water to clean the terminal.Rubbing the keys with a dry or barely moist cloth should suffice to clean them. Donot remove the keycaps to clean them more thoroughly; damage may result to theswitch contacts if they are replaced incorrectly.</P><P>Keep the ventilation slots clear. Blocking these slots by placing objects on top of orunder the VT100 may cause the terminal to overheat.</P><H2 ID="S2.2">Interface Information</H2><H3 ID="S2.2.1">EIA Interface</H3><P>The basic VT100 operates on full duplex, asynchronous communication lines. Theterminal interfaces to the line with a 25-pin connector mounted on the back of theterminal which meets the requirements of EIA specification RS-232-C. <A HREF="table2-1.html">Table 2-1</A>summarizes the EIA connector signals; the following paragraphs explain each signalas used in the basic VT100.</P><P><STRONG>Protective Ground -- Pin 1</STRONG><BR>This conductor is electrically bonded to the VT100 chassis. Use of this conductorfor reference potential purposes is not allowed.</P><P><STRONG>Transmitted Data (from VT100) -- Pin 2</STRONG><BR>The VT100 transmits serially encoded characters and break signals on this circuit,which is held in the mark state when neither characters nor break signals are beingtransmitted.</P><P><STRONG>Received Data (to VT100) -- Pin 3</STRONG><BR>The VT100 receives serially encoded characters generated by the user's equipmenton this circuit.</P><P><STRONG>Request to Send (from VT100) -- Pin 4</STRONG><BR>Asserted at all times when terminal is powered up.</P><P><STRONG>Clear to Send (to VT100) -- Pin 5</STRONG><BR>Ignored at all times.</P><P><STRONG>Data Set Ready (to VT100) -- Pin 6</STRONG><BR>Ignored at all times.</P><P><STRONG>Signal Ground -- Pin 7</STRONG><BR>This conductor establishes the common ground reference potential for all voltageson the interface. It is permanently connected to the VT100 chassis.</P><P><STRONG>Carrier Detect (to VT100) -- Pin 8</STRONG><BR>Ignored at all times.</P><P><STRONG>Speed Select (from VT100) -- Pins 11, 19, and 23</STRONG><BR>This signal is alternately called Secondary Request to Send. The basic VT100maintains this line in the asserted state at all times.</P><P><STRONG>Speed Indicator (to VT100) -- Pin 12</STRONG><BR>This signal, alternately called Secondary Carrier Detect, is ignored at all times.</P><P><STRONG>Transmission Clock (to VT100) -- Pin 15</STRONG><BR>Ignored at all times.</P><P><STRONG>Receive Clock (to VT100) -- Pin 17</STRONG><BR>Ignored at all times.</P><P><STRONG>Data Terminal Ready (from VT100) -- Pin 20</STRONG><BR>Data Terminal Ready is asserted at all times except under the following conditions:</P><OL><LI>Terminal is not powered up</LI><LI>Terminal is in LOCAL mode</LI><LI>The 3.5 second interval following the pressing of <SPAN CLASS="keyname">SHIFT</SPAN>-<SPAN CLASS="keyname">BREAK</SPAN>.</LI></OL><P><STRONG>Ring Indicator (to VT100) -- Pin 22</STRONG><BR>Ignored at all times.</P><H4 ID="S2.2.1.1">Electrical Characteristics</H4><P><STRONG>VT100 Output Voltages</STRONG> -- On signals designated "from VT100", the mark, orunasserted state, is -6.0 V to -12.0 V; the space, or asserted state, is +6.0 Vto +12.0 V.</P><P><STRONG>VT100 Input Voltages</STRONG> -- On signals designated "to VT100", -25.0 V to +0.75 Vor an open circuit is interpreted as a mark or unasserted state, and +25.0 V to+2.25 V is interpreted as a space or asserted state. Voltages greater in magnitudethan ±25 V are not allowed. These levels are compatible with EIA STD RS-232-Cand CCITT Recommendation V.28.</P><H3 ID="S2.2.2">Optional 20 mA Current Loop Interface</H3><P>In most current loop applications, the VT100 will be connected in a passive configuration-- that is, current is supplied to the VT100. In this mode, the transmitterand receiver are both passive, both optically isolated, and the transmitter goes tothe mark state when power is turned off.</P><P>Conversion from active to passive (or vice versa) requires moving a slide switch.</P><P>In active mode either the transmitter or the receiver or both may be connected sothat the VT100 sources the 20 mA of current. In active mode isolation is notpresent and the transmitter will go to the space state when power to the VT100 isturned off.</P><P><A HREF="figure2-3.html">Figure 2-3</A> shows the 20 mA current loop interface connector mounted to theaccess cover and the individual pin assignment.</P><P><STRONG>Electrical Characteristics</STRONG><BR>The electrical characteristics of the 20 mA current loop interface are shown below:</P><TABLE><COLGROUP><COL WIDTH="30%"><COL SPAN="2" WIDTH="10%"></COLGROUP><COLGROUP><COL WIDTH="30%"><COL SPAN="2" WIDTH="10%"></COLGROUP><THEAD><TR><TH COLSPAN="3">Transmitter</TH><TH COLSPAN="3">Receiver</TH></TR></THEAD><TBODY><TR VALIGN="TOP"><TD> </TD><TD>Min</TD><TD>Max</TD><TD> </TD><TD>Min</TD><TD>Max</TD></TR><TR VALIGN="TOP"><TD>Open circuit voltage</TD><TD>5.0 V</TD><TD>50 V</TD><TD>Voltage drop marking</TD><TD>--</TD><TD>2.5 V</TD></TR><TR VALIGN="TOP"><TD>Voltage drop marking</TD><TD>--</TD><TD>4.0 V</TD><TD>Spacing current</TD><TD>--</TD><TD>3.0 mA</TD></TR><TR VALIGN="TOP"><TD>Spacing current</TD><TD>--</TD><TD>2.0 mA</TD><TD>Marking current</TD><TD>15 mA</TD><TD>50 mA</TD></TR><TR><TD>Marking current</TD><TD>20 mA</TD><TD>50 mA</TD><TD COLSPAN="3"> </TD></TR></TBODY></TABLE><P>In addition to the above specifications for passive operation, active mode will placethe transmitter or receiver in series with a source of 17 V ±5 percent and 660ohms.</P><H3 ID="S2.2.3">External Video Connections</H3><P>In addition to the EIA interface, the VT100 is also capable of easily interfacing toexternal video devices. The video devices may act either as a slave to the VT100when connected to the composite video output or provide synchronized video tothe VT100 video section when connected to the video input. The external videoconnectors are the two female BNC connectors located on the back of the terminaljust below the EIA connector. The upper connector, J8, is the video input while thelower connector, J9, is the video output.</P><P><STRONG>Composite Video Output (J9)</STRONG><BR>The composite video output provides RS170-like output (see note) generated bycombining the video signal with a composite sync signal. This output contains allvideo data appearing on the VT100 screen except that video which comes fromJ8. The output has the following nominal characteristics. (Refer to <A HREF="figure2-4.html">Figure 2-4</A>).</P><OL><LI>Output impedance = 75 ohms, dc-coupled</LI><LI>Sync level = 0 V</LI><LI>Black level = approximately 0.3 V when loaded with 75 ohms</LI><LI>White level = approximately 1.0 V with a 75 ohm load</LI><LI>The composite sync waveform conforms to EIA RS170 standards. Thevertical interval is composed of six equalizing pulses, six vertical syncpulses, and six more equalizing pulses. The timing is as follows:<TABLE><TBODY><TR><TD>Equalizing pulse width</TD><TD>= 2.33µs ± 50ns</TD></TR><TR><TD>Vertical pulse width</TD><TD>= 27.28µs ± 200ns</TD></TR><TR><TD>Horizontal pulse width</TD><TD>= 4.71µs ± 50ns</TD></TR><TR><TD ROWSPAN="2">Horizontal blank width</TD><TD>= 11.84µs ± 50ns/80 column mode</TD></TR><TR><TD>= 12.34µs ± 50ns/132 column mode</TD></TR><TR><TD>Front porch</TD><TD>= 1.54µs ± 50ns</TD></TR></TBODY></TABLE></LI></OL><P CLASS="note">NOTE: The use of dc-coupling is not in strict agreementwith RS170. To agree with RS170 the output load requires a 10µFcapacitor in series with the output. Failing to do so, the 2 mA dcshort circuit current requirement is violated. This presents no problemwith most monitors which are in fact ac-coupled.</P><P><STRONG>Video Input (J8)</STRONG><BR>An analog signal applied to the video input will be "ORed" with the internal videosignal in such a way that the beam intensity at any point on the screen willcorrespond to the intensity of that signal which would tend to make the beambrighter at that point. A video signal on this input affects only the internal screen anddoes not appear on the composite video output. This input has the following nominalcharacteristics.</P><OL><LI>Input impedance = 75 ohms, dc-coupled</LI><LI>Black level = 0 V</LI><LI>White level = 1.0 V</LI><LI>Maximum continuous input = ±2.0 V</LI></OL><P>The external video source must be synchronized to the VT100; it may do this byreferencing the composite sync on the composite video output. This means thatthe VT100 video input will not synchronize with any composite video source includingthe composite video output of another VT100.</P><H2 ID="S2.3">VT100 Specifications</H2><TABLE WIDTH="100%"><COL WIDTH="30%" ALIGN="LEFT"><COL WIDTH="70%"><TBODY><TR><TH>Dimensions</TH>⌨️ 快捷键说明
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