Inter-Office MemorandumToDLS usersDateApril 12, 1982FromEd TaftLocationPARC/CSLSubjectThe Alto DLSFile[Indigo]DLS.press(edition 5)XEROX We have a dedicated Alto in operation as a terminal controller or DLS (for Data Line Scanner). Itserves as an interface between the Xerox Research Internet and low-speed lines (2400 baud or less)connecting to hardwired or dial-up terminals, outside timesharing services, and the like.The DLS provides two main services:a dial-in service, which permits outside terminals to make incoming connections (via thepublic telephone network, the Telenet communications network, or hardwired lines) andthereby gain access to servers connected to the Internet, principally Maxc, IFSs, andErnestine; anda dial-out service, which permits users of Altos and other computers in the Internet to makeoutgoing connections (via the telephone network) to external services such as timesharingsystems.There are actually two DLSs now in operation, one at PARC and one in Dallas; and an additionalDLS in El Segundo is contemplated. Information contained in this memo applies to PARC's DLSonly.1. Dial-in serviceTo access the DLS from an outside terminal, you dial an appropriate phone number (see below),connect the terminal, and issue commands to a DLS executive, which will in turn make connectionsover the Xerox Research Internet to servers such as Maxc.When you initially make contact with the DLS, it first waits for you type a single character, fromwhich it deduces the speed of your terminal and determines what to do next. You must type oneof: CTRL-C, E', e', or RETURN. The DLS then prints the greeting message:PARC DLS #n>where n is a number identifying the line to which you are connected.If the character you typed was CTRL-C, the DLS then immediately attempts to make a networkconnection to the default server host for your DLS line (which on PARC's DLS is usually Maxc). Ifthis is successful, your terminal is logically connected to that server, with no further action on yourpart.If the initial character you typed was E', e', or RETURN, or the automatic attempt at connecting tothe default server was unsuccessful, you are left talking to a simple DLS executive, whose prompt is>' at the left margin, and whose commands are described in the next section.Н]Оg║pТiНІОc8qН]rТXН-єqН5`r НІО\ЎqН]rН-єqН5`rНІОVDqН]rН-єqН5`Н]ОTюr НЭОOїsrНыОI√Т▌ПEТ▐НыОHТ■Т∙ПVНыОF▌ТПYНыОC╘П#НоО@еТ©trТюПFНоО?AТхТиП<НоО=╪ТЯП(ТРП-НоО<8Т НоО9TТ┴trП:Т┼НоО7пТ╣П0ТІП)НоО6KНыО3gТ÷П6qr Т═НыО1ЦТ╒ПNТёqrНыО0_НыО+рuТXНыО(НrТ╙ПUТ╚НыО'iТ█П.trТ▌НыО%ЕТП9НыО#ТёПbНыО!}Т⌡ПKТ°НыОЬТqrqrП,НоОqrtНоО░rНыО╚trП=НыОфТҐqrП7НыОBТ┴П.Т┼qrНыОЎТ∙ПXТ√НыО:НыОUТ⌠П+Т■qrП+НыОяТ┼ПZТ▀ НыОMТПMЪ Э>/]ЭThe Alto DLS2While you have a connection open to a server, you can also give control to the DLS executive bytyping the escape character, which is initially ASCII code 036 (CTRL-period on TI-700 terminals,CTRL-^ or CTRL-SHIFT-N on most others).If you hang up while you have a network connection open to a server, that connection isautomatically broken. If the server you were connected to is Maxc, this has the effect of causingyour job to be detached; for other servers, your session is terminated.It may happen that your network connection to the server will fail in any of a variety of ways.Usually a self-explanatory message, such as [Pup error] Tenex restarting, wait'', will be printed out.If server or network problems cause communication to fail completely, the message [Connectiontimed out]'' will be printed within one minute, and you will be left talking to the DLS executive.Phone numbers and modem typesThe DLS is accessible via several different phone numbers, reflecting the following variations inservice:Most phone numbers are located in the Palo Alto exchange, but a few are located in theSan Jose exchange so as to be reachable by a local call from the South Bay area.Most of the lines connect to 300-baud modems, but some connect to 1200-baud modems.The 300-baud modems are compatible with all types of terminals operating at 300, 150, or110 baud (30, 15, or 10 characters per second). The 1200-baud modems are compatible onlywith Vadic 3400-series modems or couplers (and, in particular, are incompatible with Bell212 or UDS modems).When you type CTRL-C as the initial character, the DLS decides what server to connect to(usually Maxc) based on which DLS line you are using. (Of course, you can override thisdefault by instead typing RETURN as the initial character and issuing the Connect host'command, described in the next section.)Complete information on phone numbers is given in a table at the end of this memo. Here is asummary of the most useful numbers:ExchangeModemDefaultNumberPhone numbertypehostof linesPalo Alto300Maxc9493-3121Palo Alto1200Maxc3493-3105San Jose300Maxc2279-8488San Jose1200Maxc1279-3166DLS dial-in executive commandsThe DLS executive has a very simple command structure. All commands are specified by a singleletter, and the DLS then types the remainder of the command word. Most commands require youeither to supply an argument or to confirm by typing RETURN. While typing an argument, you maydelete characters by typing BS or CTRL-A, or cancel the entire command by striking DEL.ByeCloses your current network connection, if one is open, and then prints Line n off''.Your line then reverts to its initial state in which it is expecting you to type one of theinitial characters (for speed determination). Hence Bye' is equivalent to hanging up anddialling in again. This is useful if you want to switch your terminal to a new speed.Connect to: hostAttempts to establish a connection to the specified server. Usually host is simply theЪНЇОfЯrТXНGОНыОbТ·Т÷ПOНыО` Тг trТхqr qrНыО_qrТqrqrНыО\1ТУП2ТЖП%НыОZґТіПCТїНыОY)ТПGНыОVDТ╧Т╨ПMНыОTюТ█П9Т▌П/НыОS<Т╡ТЁПKНыОQ╦Т╔ПbНыОMЪtТXНыОKrТ╪П!ТҐП@НыОI√НоОF╡Т╙ПGТ╚НоОE-ТУТЖП?НоОBIТ╙Т╚П7НоО@еТ·П>Т÷НоО?AТ│П&Т┌П3НоО=╪Т╚ Т╛ПOНоО<8ТНоО9TТ Т⌡qrПFНоО7пТ П6Т⌡П"НоО6KТдqrТеП0trНоО4гТП(НыО1ЦТіП(ТїП5НыО0_ТП#НоО-ztН@Н%ЮН/Н8 Н@О+ЖН%ЮН/НоО)rТ─Н@Н%ЮН1 Н8 НоО'█Н@Н%ЮН1 Н8 НоО& Н@Н%ЮН1 Н8 НоО$┘Н@Н%ЮН1 Н8 НыО лtТXНыОГrТ≤П#Т≥П;НыОcТ∙ПGТ√НыОъТ└Т┘qrП$НыО[ТqrqrП-qrНоОЧГОvНОeТґПNТўtrНОАТ√ПWТ≈НО]Т└П:Т┘НОыТ╞ПIТ╟НоО²ЧЩОТТ НbО²Ч`ОТtНО ЦrТ╠ПEtr Т╡Ъ╪Ї °?/]o┼The Alto DLS3name of a server host (e.g., Maxc'), but any Xerox Internet name or address expressionis legal.DisconnectCloses your current network connection, if one is open.Escape character = cChanges your escape character to c, where c may be whatever character you type in(RETURN and DEL are not permitted). Initially the escape character is CTRL-^ (ASCII036B).Flush typein streamDiscards all characters you have typed but that have not yet been consumed by theserver at the other end of the open connection. This is useful if you have lost control ofthe server due to having typed ahead more characters than the combined bufferingcapacity of the server and the DLS.GrapevineMakes a connection to a Grapevine unintelligent terminal server (Ernestine''). Noconfirming RETURN is required.Local echoing on/offOrdinarily, when your terminal is logically connected to a server (e.g., Maxc), that serverprovides echoing of characters you type. This command toggles a switch that determineswhether or not the DLS is to echo characters locally. The default state of the switch isoff'.Resume connectionResumes your terminal's logical connection to the server (if there is one). You use thiscommand after having typed the escape character and issued other DLS executivecommands (except Disconnect).VersionPrints the version and release date of the DLS control program.?Prints the list of commands.Hardwired linesThere are 16 lines that are hardwired to terminals in people's offices; terminals currently connectedinclude TI-700, Tektronix 4023, and DataMedia 3000. The number of hardwired lines is strictlylimited to 16, so if you want one you must negotiate with some present owner.Operation of the DLS through hardwired lines is the same as through dial-in lines except that younever dial in, data rates of up to 2400 baud (240 characters per second) are accepted, and certainparameters (default host, terminal type, screen dimensions) may be preset on a per-line basis.Telenet linesThe DLS has three terminal connections to the GTE Telenet communications network. If you takea terminal with you while travelling, you can dial-in to any local Telenet TIP and make a connectionthrough Telenet to the DLS. This service works only with 300-baud terminals (TI-700 orequivalent).ЪНЇОfЯrТXНGОНОbТ▒ПDТ▓НО` ТНоО]^ЧО]╣НО[єП7НоОXhЧГОX©НёОXhЧ ОX©tНОVўrТҐП!trtrП&НОU*qrТЇqrТ╦П4qrqНОSіrqrНоОPjЧГОPаТНОN╟ТаП&ТбП+НОM,Т┐Т└ПDНОK╗ТяП$ТрП,НОJ#ТП#НоОFХЧ)ОG?НОE-ТяП?ТрНОC╘Т qrНоО@nЧГО@еНО>ЁТ┬П[НО=/Т┌Т┐ПDНО;╚Т⌠ Т■ПKНО:'НоО6КЧО7BТНО51Т⌠Т■ПBНО3ґТХП/ТИНО2)ТНоО.МЧЩО/DНО-3П?НоО)ВЧ▐О*NНО(=НыО$┘tТXНыО!═rТ⌠Т■ПNНыО ТЇПUТ╦НыО≤ТПMНыОЁТ≥Т ПUНыО/ТіП@ТїП"НыО╚ТчП/ТъП/НыОРtТXНыО rТ▐П^НыО┴Т┘П8Т├qrНыОТТП<НыО │ЪЙЇ :>/Zя?The Alto DLS4If you would like to use this service, contact Ron Weaver to make the necessaryarrangements.2. Dial-out serviceThe dial-out service enables you to make outgoing connections through the DLS from your Alto.This service is presently being provided without any controls or accounting, and all phone chargesare billed to PARC. It is our hope that this arrangement will prove adequate and will not be abused.If you intend to use the dial-out service, please send a message to Ron Weaver before using it for the first time. You should be aware of the following points:The principal intended clients for this service are the PARC librarians, who depend on itvery heavily in their day-to-day operation. There are only three 300-baud and three 1200-baud dial-out lines (the latter are also the only Palo Alto 1200-baud dial-in lines). Extensiveuse of this service by other users may require negotiation to avoid conflict with the library.Calls originate in Palo Alto, and are charged at regular business phone rates. Please refrainfrom making calls outside the Palo Alto calling area unless absolutely necessary.How to use itYou access the DLS dial-out service by running Chat on your Alto and making a connection to theDLS. Assuming you have Chat.run on your disk, simply type:>Chat ParcDLS+300 RETURNto access a 300-baud line, or>Chat ParcDLS+1200 RETURNto access a 1200-baud line.If the DLS is operating normally, you will shortly see the message:PARC DLS dial-out server, line n (b baud)>If all the dial-out lines of the speed you requested are in use, Chat will display a message to thateffect and will not complete the connection to the DLS.The dial-out server has a simple executive with a small number of single-character commands.When you see >' at the left margin, the DLS executive is waiting for you to type a command. Nowtype:>Call phone number xxx-xxxx RETURNthat is, C' followed by the phone number you want to dial, terminated by RETURN. The DLS willproceed to dial the number.If the call is answered and the correct answering tone is heard, the DLS will display the messageCall completed'', perhaps followed by a greeting from the computer system you called. Thereafter,all characters you type will be sent over the phone connection, and all characters received over thephone connection will be displayed on your Alto screen.If the number you dialled is busy or doesn't answer within 30 seconds, the message Failed tocomplete connection'' will appear, and control will return to the DLS executive. Unfortunately, theDLS can't distinguish between the busy and no-answer conditions. Problems other than busy andno-answer will result in the message Dialler or phone system malfunction''.To terminate the connection, first log out from the remote computer in whatever way is appropriate.The easiest next step is simply to Quit out of Chat (with BLANK-MIDDLE Q or SHIFT-SWAT). Thisboth hangs up the DLS dial-out line and breaks the connection between your Alto and the DLS.ЪНЇОfЯrТXНGОНыОbТЄП.Т╣П.НыО` НыО\uТXНыОY)rТ╚ПIТ╛НыОW╔Т║ПZТ╒НыОV!Т┌qrТ┐П=НыОS<ТюПCТаНыОQ╦ТПQНоОNсТ╣П9qrТІНоОMOТ⌡ПAТ°НоОKкТ┐Т└ПAНоОJGТ⌠ Т■ПSНоОGbТ█ПGТ▌НоОEчТПQНыОB%tТXНыО?ArТ▌ПDТ▐НыО=╪ТП;НоО:ьНО:│Ч&О:ьТ─Н%О:│ЧЕО;eqН)─О:ьrТНоО9 НО8ІЧжО9 Т─НуО8ІЧЕО9 qН)─О9 rТНыО6(ПCНоО3CtrtrНоО1©НыО.зТ╒П\ТёНыО-VТП7НыО*rТрТсПEНыО(НТ┐ПLТ└НыО'iНоО$┘НО$.ЧЩО$┘ТН=О$.ЧЦО$┘trН& О$.ЧЕО%qНыО!═rТ░ПIТ▒qrНыО ТНыО7ТїП1Т╗П0НыОЁТ┬П$Т┴П@НыО/Т≈ Т≤ПVНыО╚ТП7НыОфТаПJТбНыОBТ▐ПdНыОЎТ║ПZТ╒НыО:ТПMНыОUТ├ПFТ┤НыОяТ═П:qrq rТ║НыОMТїП\зЇ?/]kThe Alto DLS5You can also return control to the DLS executive by typing CTRL-_ (CTRL-left-arrow), then breakthe connection using the Disconnect command, described in the next section.If the phone connection is broken because the remote computer hangs up, the message Dial-outconnection broken'' is displayed and control returns to the DLS executive.Dial-out server executive commandsYou can type any of the following commands when you see >' at the left margin. You mustterminate all commands with RETURN.Baud rate = numberSets the speed of the dial-out connection. Only 300-baud lines may have their speedchanged in this manner, and legal values are 300, 150, and 110.Call phone number numberDials the phone number you specify, as described above. The phone number may beup to 15 digits long. The forms nnn-nnnn' and (nnn) nnn-nnnn' are accepted, or youmay type the entire phone number without punctuation. (In fact, parentheses andhyphens are simply ignored.)DisconnectBreaks the dial-out connection, by hanging up the phone line. Control remains in theDLS executive.Escape character = cChanges your escape character to c, where c may be whatever character you type in(RETURN and DEL are not permitted). Initially the escape character is CTRL-_ (ASCII037B).QuitBreaks the dial-out connection (if there is one), and then breaks the connection betweenyour Alto and the DLS dial-out server.Resume connectionResumes your dial-out connection (if there is one). You use this command after havingtyped the escape character and issued other DLS executive commands (exceptDisconnect).Other notesTo capture your dialog in a file, enable the Chat typescript feature by typing MIDDLE-BLANK Tfollowed by a file name and RETURN. When you are done, type MIDDLE-BLANK T RETURN to closethe typescript file; or alternatively just Quit from Chat. The typescript file will be on your Altodisk, and you can edit it, print it, etc., in the usual fashion. (Alternatively, you can specify a Chattypescript file by an appropriate entry in your User.cm.) Further information about Chat may befound in the Alto Non-programmer's Guide and in the Chat documentation (fileChat.tty).You can get the DLS dial-out server to generate a long space'' by typing CTRL-SPACE on your Altokeyboard; this is equivalent to pressing the BREAK key on ordinary terminals.You can connect to a specific DLS line by means of the command Chat ParcDLS+1000xx'', wherexx is the desired line number. At present, the main use of this feature is connecting to GSL's Vaxcomputer, which is hardwired to DLS line 13 (i.e., ParcDLS+100013), and to CSL's WWV timereceiver, which is on line 15 (ParcDLS+100015).НЇОfЯrТXНGОНыОbТёП;qrqrТєНыО` ТПKНыО]╣Т╚ПGТ╛НыО\1ТПJНыОXxtТXП"НыОU■rТцПYНыОTТqrНоОPтЧГОQ+ Н┐ОPтЧ]ОQ+tНОOrТўТ╞ПLНОM∙ТП?НоОJZЧЩОJ╠Н█ОJZЧ]ОJ╠tНОH÷rТєП#Т╔П-НОGТ÷Т═trtrtrНОE≈ТьТыПHНОDТНоО@вЧОA.НО?Т║П-Т╒П(НО=≥Т НоО:]ЧГО:ЄНёО:]Ч О:ЄtНО8ёrТҐП!trtrП&НО7qrТ╠qrП8qrqНО5⌡rqrНоО2_ЧО2ІНО0╔Т▄ Т█ПNНО/!ТП&НоО+ЕЧО,<НО*+Т█ПIТ▌НО(їТ0ПBТ1НО'#НыО#jtТX НыО ├rТҐТЎП6qrНыОТ┬qrТ┴qrqrНыО}ТўПZТ╞ НыОЫТ≈Т≤ПRНыОuТ╒ТёПQНыОЯТ²П"Т·П*НыОmНыО┬Т┴Т┼П8q rНыОТП-qrНыО Т┌П/Т┐П#trНыО⌡trТ░ПIТ▒НыО ТЁПPТЄНыО⌠ТП/ |ЇL>/\©uThe Alto DLS63. Current configuration, phone numbers, etc.The DLS line configuration changes occasionally; its current state is given in file[Indigo]ParcDLS.config, which is a text file that is read by the DLS control program todetermine how it is to treat each line. This file specifies terminal parameters, phone numbers fordial-in lines, and owners and office numbers of hardwired lines. A copy of this file appears below.Contents of DLS.config, as of April 10, 1982// Hardwired lines00 Hardwired Host Maxc// Maxc room01 Hardwired Host Maxc// Maxc room02 Hardwired Host Maxc Type 10 Length 24 Width 80// 35-200303 Hardwired Host Maxc Type 10 Length 24 Width 80// 35-3021 L. Anderson04 Hardwired Host Maxc// 35-1014 & 1048 Cheng05 Hardwired DialOutOnly Baud 2400// 35-2088 Stewart06 Hardwired Host Maxc Type 10 Length 24 Width 80// 35-200807 Hardwired DialOutOnly Baud 1200// 35-3028 XCS (Don Curry)10 Hardwired Host Maxc Type 10 Length 24 Width 80// 35-2058 M. Kay11 Hardwired Host Maxc Type 10 Length 24 Width 80// 35-210412 Hardwired DialOutOnly Baud 2400// 35-2116 Hermes Nova13 Hardwired DialOutOnly Baud 1200// 35-1151 Vax14 Hardwired Host Maxc Type 10 Length 24 Width 80// 35-Receptionist15 Hardwired DialOutOnly Baud 2400// 35-2077 WWV receiver16 Hardwired DialOutOnly Baud 2400// 35-2073 EtherPhone17 Hardwired Host Maxc// 35-2100 Taft// Incoming Telenet lines20 Telenet Control 40 Baud 300 Host Maxc21 Telenet Control 41 Baud 300 Host Maxc22 Telenet Control 42 Baud 300 Host Maxc// The following are 300-baud, dial-in only, San Jose exchange23 Dataset Control 43 Host Maxc// 279-8489 rotary [2]24 Dataset Control 44 Host Maxc// 279-8488 rotary [1]// The following is 1200-baud, dial-in only, San Jose exchange25 Dataset Control 45 Host Maxc// 279-3166// The following is 300-baud, dial-in or dial-out, Palo Alto exchange// (more of these below)26 Dataset Control 46 DialOut 15 1 Host Maxc// 493-2130// 493-3104 rotary [10] not currently connected to the DLS// The following are 300-baud, dial-in only, Palo Alto exchange27 Dataset Control 47 Host Maxc// 493-3129 rotary [9]30 Dataset Control 50 Host Maxc// 493-3128 rotary [8]31 Dataset Control 51 Host Maxc// 493-3127 rotary [7]32 Dataset Control 52 Host Maxc// 493-3126 rotary [6]33 Dataset Control 53 Host Maxc// 493-3125 rotary [5]34 Dataset Control 54 Host Maxc// 493-3124 rotary [4]35 Dataset Control 55 Host Maxc// 493-3123 rotary [3]36 Dataset Control 56 Host Maxc// 493-3122 rotary [2]37 Dataset Control 57 Host Maxc// 493-3121 rotary [1]// The following are 300-baud, dial-in or dial-out, Palo Alto exchange// (another of these above)66 Dataset Control 67 DialOut 12 1 Host Maxc// 493-156370 Dataset Control 71 DialOut 11 1 Host Maxc// 493-1510// The following are 1200-baud, dial-in or dial-out, Palo Alto exchange72 Dataset Control 73 DialOut 7 0 Host Maxc// 493-3139 rotary [3]74 Dataset Control 75 DialOut 5 0 Host Maxc// 493-3107 rotary [2]76 Dataset Control 77 DialOut 1 0 Host Maxc// 493-3105 rotary [1]ЪНЇОfЯrТXНGОНыОbuП-НыО_9rТ┬ПEТ┴ НыО]╣ТнП9ТоП#НыО\1ТёТєПGНыОZґТ▒П]Т▓НыОVТtТXП,НыОTVvТFНыОSН3юvНыОQ╦Н3юvНыОPzП1Н3ю НыОO`П1Н3юНыОN#Н3юvНыОLбП"Н3юvНыОK└П1Н3ю НыОJGП"Н3юvНыОI П1Н3юНыОGОП1Н3ю НыОF╡П"Н3юvНыОEQП"Н3юv НыОDП1Н3юНыОBжП"Н3юvНыОAuП"Н3юvНыО@Н3юvНыО=╪НыО<╒П(НыО;┬П(НыО:nП(НыО89П>НыО6ЭН3юvНыО5⌡Н3юvНыО3CП>НыО2Н3юv НыО/ўПEНыО.■НыО-VП,Н3юv НыО*ЪП:НыО(йП?НыО'█Н3юvНыО&,Н3юvНыО$кН3юvНыО#jН3юvНыО" Н3юvНыО ╘Н3юvНыОHН3юvНыОГН3юvНыО┤Н3юvНыО/ПFНыОНыОвП,Н3юv НыОvП,Н3юv НыОПGНыОАП+Н3юvНыО─П+Н3юvНыО П+Н3юvўЇы>/X2G TIMESROMAN TIMESROMAN TIMESROMAN LOGO TIMESROMAN TIMESROMAN HELVETICAИvа∙▀&╧.ЪЪj/1/≤Ав)ЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪ DLS.bravoTaft.PAApril 12, 1982 10:38 AM