Economical Terminal Servers
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1. and prevent them from issuing privileged com Terminals 2 4 as seen by PC with ter minal emu lation soft ware SALES mands Enable password protection for privileges ports services and remote access Users can lock and unlock ports via pass words e Power on diagnostics pin point trouble with network and serial lines e You can use SLIP or PPP to access the Internet by ter minals or PCs connected to the Terminal Server s serial port Models supporting TCP IP and LAT protocol provide e DEC compatibility The units are fully compatible with most DEC operating systems since they support LAT and NCP e Host initiated transfers Hosts can share modems and printers when a Terminal Server is config ured to provide its attached devices as services to other nodes Jobs can be queued concurrently to Terminal Servers services by TCP IP and LAT hosts Remote console support DEC NCP and TSM facili ties can be used to config ure multiple port Terminal Servers from a remote loca tion UNIX managers can support remote consoles via Telnet ed Tech Glossary Host A computer attached to a network A host is generally an interactive com uter that enables users to og in Local Mode Mode in which the user issues commands directly to the Terminal Server Node An intelligent device for example a host an Ethernet workstation or a Terminal Server2. with a direct connection to the Ethernet network and an Ethernet address Devices connected to a Terminal Server serial port are excluded from this category Point to Point Protocol PPP A suite of protocols that are used to encapsulate protocols other than just TCP IP Similar to SLIP but is a more robust full featured protocol PPP is extensible via automatic negotiation to allow interoperability between a wide range of products During negotia tion each end of the link advertises which features it has implemented and the peers agree on a common set of features to be used Reverse Telnet When the Terminal Server provides a service to a LAT VMS host the connection is often referred to as Reverse LAT in that normal LAT connec tions are logins from a Terminal Server to a host Hosts request reverse LAT connection a LAT solicit message when wishing to access a service such as a printer or modem connected to the Terminal Server Serial Line IP SLIP A com mon non standard method of sending Internet Protocol IP over low speed point to point links SLIP provides a very simple framing scheme for sending IP packets over a serial line and works ona simple dedicated character oriented asynchronous line like Service A device that can establish a network connec tion such as a host that ter minals can connect to 13576 Hot Topics v All models of the Terminal Ser
3. lt BLACK BOX Economical Terminal Servers UCN ol Economical Terminal Servers connect your ASCII devices to an Ethernet network Choose the single port model to connect one device using TCP IP choose a multiple port model to connect four to eight devices using TCP IP or LAT protocol Key Features Supports command line editing recall and comple tion Software upgrades are a breeze they re immediately downloaded when the power comes on Small and quiet fits where you need it and operates without a fan Runs multiple LAT and Telnet sessions simultaneous ly Provides a direct connection to the network for your devices 13576 Overview too Servers are used to connect your PCs ASCII terminals printers and modems to an Ethernet LAN They give your users asyn chronous connections when ever you need them in the office lab computer or branch offices Wiring is neat and simple Your terminals and printers merely need a physical connection to the Server which connects via a single wire to the Ethernet backbone Terminal Servers will establish sessions between your terminals and printers and any of the hosts connect ed the the Ethernet support ing the LAT or TCP IP proto col suites Workstations and PCs supporting TCP IP over seri al lines can connect to the Terminal Server s serial ports using the PPP or SLIP proto col This type of connection provides a hi
4. LE2508A R2 LE2608A R2 4 3 x 216 29 7 cn 17 HX 8 5 W x 11 7 D Weight LE2101A R2 LE2101 AE R2 0 5 kg 1 Ib LE2104A R2 LE2204A R2 LE2508A R2 LE2608A R2 2 1 kg 4 7 lb 7v The complete package What you get when you order the Terminal Server All models e Terminal Server Single port models e Power supply e User s manual Multiple port models e Power cord Ordering Information This information will help you place your order quickly PRODUCT NAME Economical Terminal Servers 1 Port 1OBASE T 10BASE T BNC 4 Port TCP AUI ORDER CODE LE2101 AE T R2 LE2101 AE BI R2 LE2104A AUI R2 LE2104A BNC R2 LE2104A TP R2 LE2204A AUI R2 LE2204A BNC R2 LE2204A TP R2 LE2508A AUI R2 LE2508A BNC R2 LE2508A TP R2 LE2608A AUI R2 LE2608A BNC R2 LE2608A TP R2 TCP LAT AUI TCP LAT BNC LAT TCP UTP 8 Port TCP AUI TCP LAT AUI TCP LAT BNC TCP LAT TP
5. apabilities of their peer For example a terminal might support full cursor control characters Once the connec tion is established the termi nal and host may agree to support the extra characters This all happens transparent ly to the user who sees only a login screen and none of the mechanics Unlike LAT network service with its multicasts TCP IP implementations generally have no knowl edge of remote hosts until a connection is attempted There is no TCP IP parallel to the SHOW SERVICES commands Until the actual connection request is made a host is not searched for Hosts using TCP IP fre quently see only a fraction of the hosts on the whole net work Usually a TCP IP network is broken down into subnetworks where a host is able to see only the hosts on its own subnet TCP IP hosts generally have both an alphanumeric IP host name such as SALES and a numeric IP address such as 192 114 22 97 v Some of the multiport Terminal Servers support Local Area Transport LAT protocol developed by Digital Equipment Corporation DEC igital Equipment Corporation s LAT Local Area Transport networking software is designed to make local area networks easy to access and manage LAT software is built around the concept of services A service may be provided by a dedi cated device such as a print er or by a network host A node is a device on the net work that allows one or more s
6. ervices to be accessed such as a computer you can log in to A Terminal Server is also a node since it can offer serv ices and logins Services are named and more than one service on a network can have the same name For example you could attach eight modems to a Terminal Server and set up the service modem to use ports 1 8 A user who types CONNECT MODEM does not necessarily know which of the modems he or she would be connected to The first diagram on page 2 shows an example of a net work with services Multicasts are advertise ments containing the name and list of services of various nodes By monitoring multi cast messages all hosts on the network know what nodes and services are avail able and can provide this information to their interac tive users The SHOW SER VICES and SHOW NODES commands display this infor mation A rating for each service offered is contained in multi cast messages This rating is an estimate of how busy that service is Ratings range from 0 to 255 0 means the service is unavailable while 255 means the service is available and has no current users Since ratings are used to determine to which service a user will be connected when a choice is available service ratings may concern even casual users LAT also implements serv ice groups Each port on the Terminal Servers or any Terminal Server and service on the network can be thought of as belonging to one or more
7. gh speed low cost full IP network link for many uses such as Telnet file transfer and client server distributed applications Terminal Servers will Connect your async devices to an Ethernet using your choice of protocols TCP IP or LAT increase your productivity by letting users access any of the hosts on the LAN from a sin gle terminal Users can initi ate multiple concurrent ses sions and switch between them with a single keystroke Choose from Thick Thin or UTP Ethernet connections v Typical Applications Set up a Local Area Network using DEC LAT protocol Share services such as a printer among several connect ed devices such as a group of PCs Set up a Wide Area Network using TCP IP protocol Access a remote server from a virtual terminal which can be located thousands of miles away from the server Create a LAN using Below is a typical application of a LAN using Network Services DEC LAT protocol s ae network services Or set up a WAN using a TCP IP Telnet con nection to access a DEC remote host Thee Ethernet backbone Terminal Server 4 Port LE2204A R2 i Terminals Service Name Modem for a Bank of Modems Terminals Async Port on Remote DEC Host Modem Below is a typical application of a LAN WAN using a Telnet Connection i Technically Speaking mae Terminal server 4 Port 1 LE2104A R2 ____ he Terminal Servers are available in a variety
8. groups When a user or device requests a service connection the LAT host checks to see if the groups that the requester belongs to match up with those of the service request aN Specifications Protocol LE2101A R2 LE2101AE R2 LE2104A R2 LE2508A R2 LAN TCP IP LE2204A R2 LE2608A R2 LAN TCP IP LAT Serial ports None PPP SLIP Indicators LE2101A R2 LE2101AE R2 1 Power LED 1 LAN 1 Port 1 ERR Error LE2104A R2 LE2204A R2 LE2508A R2 LE2608A R2 1 Power LED 1 LAN and 1 Activity for each port Connectors LE2101A T R2 LE2101 AE T R2 1 DB25 1 RJ 45 LE2101A BT R2 LE2101AE BT R2 1 DB25 1 RJ 45 1 BNC All multiport models 1 IEC 320 power connector 1 DB25 female paral lel AUI multiport mod els 1 DB15 female and 4 or 8 RJ 45 serial BNC multiport models 1 BNC and 4 or 8 RJ 45 serial TP multiport models 1 RJ 45 1OBASE T and 4 or 8 RJ 45 serial 13576 Speed Ethernet 10 Mbps Serial Up to 115 Kbps Operating Temperature 0 to 50 C 32 to 122 F Humidity 5 to 90 non condensing Power LE2101A R2 Input 120 VAC 60 Hz Output 12 VDC 800 mA 9 6 VA LE2101AE R2 Input 220 VAC 50 Hz Output 12 VDC 800 mA 9 6 VA LE2104A R2 LE2204A R2 LE2508A R2 LE2608A R2 100 230 VAC autosensing Size LE2101A R2 LE2101AE R2 3 8 x 11 4 x 19 cm 1 5 H x 4 5 W x 7 5 D LE2104A R2 LE2204A R2
9. of models and work with sever al protocols to fit your appli cation Additional features help you manage your net work e The Single Port Terminal Server lets you connect one device to an Ethernet run ning at up to 115 2 Kbps One model has a connec tion for a 1OBASE T Ethernet device while another model has connec tions for either a 1OBASE T or a ThinNet device All models support TCP IP The multiple port Terminal Servers can connect to stan dard Thin or 1OBASE T Ethernet networks There are models for 4 or 8 serial device connections Some models support TCP IP and some models support both TCP IP and LAT pro tocol All models provide e UNIX compatibility Telnet is supported by almost all UNIX systems The Terminal Servers support Domain Name Servers and a host table that contains IP addresses of frequently used hosts 13576 Server SALES P N e Remote console support Simple configuration of the single or multiple port Terminal Servers by UNIX managers is provided by Telnet SNMP tThe Simple Network Management Protocol provides an over all view of network load error conditions and prob lem sites Security Limit user access to services via group codes Or configure the Terminal Server to log out a session automatically when a device is turned off or when a port is disconnect ed Set time limits to user sessions Give ports a lim ited view of the network
10. vers support Transmission Control Protocol internet Protocol TCP IP described below Eo is an industry stan dard network terminal pro tocol It allows a user any where on the network to access a foreign host and start a terminal session The user need not worry about what kind of computer the foreign host is or what operating sys tem it uses and the remote host will know nothing about the user terminal type This is essential for the wide area networks that Telnet was designed for Networks that support Telnet can stretch for thousands of miles and con tain thousands of hosts Telnet accomplishes this com patibility using virtual termi nals Any Telnet connection looks the same from both sides of the network The second diagram on page 2 illustrates a simple Telnet connection All terminals on the net work in this figure can access all hosts but do not need to nor can they know exactly what type of hardware the host is Theoretically termi nal 4 in the example could establish a Telnet session with host SALES and would see the same type of session as would terminal 1 which is directly connected SALES the CPU will treat terminal 4 as if it were also directly con nected A Telnet connection begins with both sides of the connec tion assuming the other ter minal is dumb that is knows little about characters fonts cursor movement etc The two sides then negotiate options to determine the c
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