Xref: bloom-picayune.mit.edu comp.dcom.isdn:337 news.answers:2149 Path: bloom-picayune.mit.edu!mintaka.lcs.mit.edu!yale!yale.edu!spool.mu.edu!agate!xcf.Berkeley.EDU!welch From: welch@xcf.Berkeley.EDU (Sean N. Welch) Newsgroups: comp.dcom.isdn,news.answers Subject: ISDN Frequently Asked Questions (and Answers) [Monthly posting] Summary: This posting contains a list of Frequently Asked Questions (and their answers) about Integrated Services Digital Networking (ISDN). It should be read by anyone who wishes to post to the comp.dcom.isdn newsgroup. Keywords: ISDN FAQ Message-ID: Date: 13 Jul 92 23:02:23 GMT Article-I.D.: xcf.isdn-faq_711068602 Expires: 26 Aug 1992 23:03:22 GMT Reply-To: welch@xcf.Berkeley.EDU (Sean N. Welch) Followup-To: comp.dcom.isdn Organization: Experimental Computing Facility, U.C. Berkeley Lines: 569 Approved: news-answers-request@MIT.Edu Supersedes: NNTP-Posting-Host: xcf.berkeley.edu Originator: welch@xcf.Berkeley.EDU Archive-name: isdn-faq Last-modified: 1992/07/10 Version: 1.0 This is the first official monthly posting of this comp.dcom.isdn FAQ. Thank you all for your feedback on the initial draft. (That is not to say that this is finished by any means. Comments and suggestions are always welcome.) There have been a number of additions and a few corrections since the draft and the questions and answers are no longer direct quotes. As new information was brought to my attention, it became difficult to integrate direct quotes. If there are any problems with my editing as opposed to quoting, I'm sure someone will let me know. Now I just cite the sources at the end of each question. It still reads like it was written by 40 different people (because it was) but after a few revisions, I hope to have a much smoother document. I'm currently working on two additional questions having to do with the nitty-gritty of how ISDN is carried and Switched 56 Kbps (S56) as it relates to ISDN. Look for them next month. [Note to the moderator of news.answers: Sorry for all the trouble. Thanks.] ----- Sean N. Welch \\/ welch@xcf.Berkeley.EDU Experimental Computing Facility /\\ University of California, Berkeley ----- Frequently Asked Questions and Answers comp.dcom.isdn These questions and answers have (for the most part) been extracted from comp.dcom.isdn. Questions with answers: 1) What is ISDN? 2) What does an ISDN network look like? 3) What is ATM? 4) What will it look like in my house/office? 5) How does this compare to regular phone line services? 6) Is caller ID available on ISDN? 7) What do I get above and beyond plain old telephone service? 8) What do ISDN phones cost? 9) Can you use existing telephone equipment with the voice portion? 10) How do I find out about getting ISDN in my area? 11) Where can I find what all of these acronyms mean? 12) Who is shipping what? 13) How about that SPARCstation 10? 14) Why does certain ISDN TE only work with a specific ISDN switch? 15) Where can I read more? 16) Who do I have to thank for this list? Questions for which I have not yet put together an answer, but for which I am accepting suggestions: a) What is ISDN-1? b) What is the status of ISDN-1? c) What is B-ISDN and what does it have to do with ISDN? Suggestions for additional questions and answers are appreciated. --- 1) What is ISDN? ISDN stands for "Integrated Services Digital Networks", and it's a CCITT term for a relatively new telecommunications service package. ISDN is basically the telephone network turned all-digital end to end, using existing switches and wiring (for the most part) upgraded so that the basic "call" is a 64 kbps end-to-end channel, with bit-diddling as needed (but not when not needed!). Packet and maybe frame modes are thrown in for good measure, too, in some places. It's offered by local telephone companies, but most readily in Australia, France, Japan, and Singapore, with the UK and Germany somewhat behind, and USA availability rather spotty. eleskg@nuscc.nus.sg (Winston Seah) goldstein@carafe.enet.dec.com (Fred R. Goldstein) paul@suite.sw.oz.au (Paul Antoine) --- 2) What does an ISDN network look like? A Basic Rate Interface (BRI) is two 64K bearer ("B") channels and a single delta ("D") channel. The B channels are used for voice or data, and the D channel is used for signaling and/or X.25 packet networking. This is the variety most likely to be found in residential service. Another flavor of ISDN is Primary Rate Interface (PRI). Inside the US, this consists of 24 channels, usually divided into 23 B channels and 1 D channel, and runs over the same physical interface as T1. Outside of the US then PRI has 31 user channels, usually divided into 30 B channels and 1 D channel. It is typically used for connections such as one between a PBX and a CO or IXC. kevinc@aspect.UUCP (Kevin Collins) keyman@doorway.Eng.Sun.COM (Dave Evans) turtle@newshub.sdsu.edu (Andrew Scherpbier) --- 3) What is ATM? ATM (Asynchronous Transfer Mode) is a switching/transmission technique where data is transmitted in small, fixed sized cells (5 byte header, 48 byte payload). The cells lend themselves both to the time-division- multiplexing characteristics of the transmission media, and the packet switching characteristics desired of data networks. At each switching node, the ATM header identifies a "virtual path" or "virtual circuit" that the cell contains data for, enabling the switch to forward the cell to the correct next-hop trunk. The "virtual path" is set up through the involved switches when two endpoints wish to communicate. This type of switching can be implemented in hardware, almost essential when trunk speed range from 45Mb/s to 1Gb/s. For more information, read comp.dcom.cell-relay. art@acc.com (Art Berggreen) --- 4) What will Basic Rate (2B+D) ISDN look like in my house/office? An ISDN BRA U-Loop is 2 conductors from the CO to the customer premises. At the customer premises the U-loop is terminated by an NT1 (network termination 1). The NT1 drives a T-bus which is 4 wires. You can only have one device on the T-bus. If you run the T-bus into a NT2 which has an S-bus (the passive bus) on the other side, you can connect up to 8 physical devices. Electrically, the S and T reference points are the same (which is why they are almost always referred to as the S/T bus). Some NT1 may include between 24v and 53.5v power on the T-bus (making it 6 wires), however this would be model/vendor dependent. There are also 8 wire T-bus connection (power + 2 extra?). Australia and Europe are similar except the NT1 is owned by the PTT. Either a ECH (Echo Canceling Hybird), like is used in the US, or a form of time division multiplexing using AMI is used to achieve bidirectional transmission an a single pair. +-+ S Bus +-------+ T Bus +-------+ U Loop | |?|=-=-=-=-=-=| NT2 |===========| NT1 |--------------[| wall +-+ 4-8 wires +-------+ 4-8 wires +-------+ 2-4 wires | Some ISDN hardware plugs into the U loop, some with the T Bus, and some with the S-Bus. In the US (at least) there is a power supply between the wall and the NT1. cliff@Berkeley.EDU (Cliff Frost) curt@kcwc.com (Curt Welch) dror@digibd.com (Dror Kessler) glarson@bnr.ca (Greg Larson) paul@suite.sw.oz.au (Paul Antoine) pturner@eng.auburn.edu ( Patton M. Turner) ronnie@cisco.com (Ronnie B. Kon) --- 5) How does this compare to regular phone lines? The ISDN line may act like two independent phone lines with two numbers. Depending on the CO equipment, conferencing features etc. may be available (conferencing in the telephone switch). BRA ISDN phones can support key-set features such as you would expect to get on an office PBX like: - multiple DNs / lines. - conferencing features. - forwarding features. - speed call. - call park. - call pickup. - ring again. curt@kcwc.com (Curt Welch) glarson@bnr.ca (Greg Larson) --- 6) Is caller ID available on ISDN? Caller ID (name or number display) may be supported (depending on the CO setup). The availability of caller ID for residential phones would depend on the capabilities of the local phone network and legislation allowing or disallowing caller ID. curt@kcwc.com (Curt Welch) glarson@bnr.ca (Greg Larson) --- 7) What do I get above and beyond plain old telephone service? One of the main features it that instead of the CO sending an AC ring signal to activate your bell, it sends a digital package that tells WHO is calling (if available), WHAT TYPE of call (speech, datacomm?), the NUMBER DIALLED (maybe one of your aliases) and some other stuff. Your equipment can then analyze this stuff and make an "intelligent" decision what to do with it. For example, a phone (with speech-only capacity) would completely ignore a datacomm call while a Terminal Adapter (ISDN "modem") or a phone with built-in datacom functions would respond to it. If you have several "aliases" tied to your line, you can program certain phones to answer calls for certain numbers only. Datacomm calls contain baud rate and protocol information within the setup signal so that the connection is virtually instantaneous (no messing around with trying different carriers until both ends match). curt@kcwc.com (Curt Welch) etxorst@eos.ericsson.se (Torsten Lif) --- 8) What do ISDN phones cost? The ISDN sets can cost between $180 for an AT&T 8503T ISDN phone from Pacific Bell up to $1900 depending on what/how many features are needed. keyman@doorway.Eng.Sun.COM (Dave Evans) huntting@futureworld.advtech.uswest.com (Brad Huntting) spike@coke.std.com (Joe Ilacqua) --- 9) Can you use existing telephone equipment with the voice portion? Terminal Adapters (TA'a) are available that will interface non ISDN terminal equipment (TE), called TE2 to the S/T interface. At least one RBOC provides a modem pool to allow for interchange of data with POTS subscribers. Bellcore may approve a standard to allow a analog pair to interface to POTS sets from a NT1. Also w/o a NT2 only one set can be connected to a B channel at a time. This prevents 2 sets from participating in the same voice call. pturner@eng.auburn.edu ( Patton M. Turner) spike@coke.std.com (Joe Ilacqua) --- 10) How do I find out about getting ISDN in my area? I work in the industry and suggest that you call the local telephone service center office and ask for the name and number of the Marketing Product Manager for ISDN services. If the service rep cannot make heads or tails of your question, ask to speak to the local service center manager for complex business services. This person should be able to direct you to the right place. For the Bell companies, this position is normally part of the telephone company's core marketing staff at their headquarters location. [I had been planning on listing particulars about local people to contact, but since people change jobs and I wasn't planning on continually verifying the names and numbers, instead I'll stick with listing the following.] Bellcore national ISDN information clearing house hotline 800 992 4736 North American ISDN Users Forum (NIU) is an org. of ISDN-interested parties, coordinated by NIST (National Institute of Stds. and Tech.) Contact: Shukri Wakid Advanced Systems Division NIST Gaithersberg, MD (301) 975-2937/4853 bharrell@garfield.catt.ncsu.edu (Ben Harrell) elitman@wam.umd.edu (Eric A. Litman) evans@zk3.dec.com (Marc Evans) varney@ihlpf.att.com (Al Varney) --- 11) Where can I find what all of these acronyms mean? An archive of telecommunication related files are maintained on lcs.mit.edu in the telecom-archives sub directory. There is a glossary of general telecom acronyms, as well as an ISDN specific list. jms@romana.Tymnet.COM (Joe Smith) asks: PMW1@psuvm.psu.edu (Peter M. Weiss) --- 12) Who is shipping what? [In this section, I'd like to expand a list of vendors shipping products related to work in ISDN. As it stands, the number is small, and the information is sparse. Additions and corrections are most welcome.] [Also - Network World from November 18th, 1991 has an extensive listing of products that were available at that time. It ranges from terminal adapters and PC cards to handsets to VME boards. I'm in communication with them trying to get permission to reproduce parts of the article here.] Digital Subscriber Controler AMD79C30A ISDN chip Combines IEEE 1.430 S/T interface transceiver B channel LAPD channel processor and audio processor in a single chip. Advanced Micro Devices 901 Thomson place Mailstop 126 Sunnyvale, CA 94086 (408) 732 2400 (voice) ISDN <-> other network converters Combinet 333 West El Camino Real, Suite 310 Sunnyvale, California 94087 (408) 522 9020 (voice) (408) 732 5497 (fax) ISDN <-> other network converters DigiBoard 6400 Flying Cloud Drive Eden Prarie, MN 55344 (612) 943 9020 (voice) (612) 643 5398 (fax) Q-bus board, router, and PC cards Digital Equipment Co REO2 G/H2 DEC Park Worton Grange Reading Berkshire England PC cards and standalone ISDN adapters Gandalf Cherry Hill Industrial Center Building 9 Cherry Hill, NJ 08002 1 800 GANDALF (voice) Terminal adapters Hayes ISDN Technologies 501 Second St., Suite 300 San Francisco CA 94107 (415) 974-5544 (voice) (415) 543-5810 (fax) ISDN Product Manager: Chris Brock (cbrock@hayes.com) ISDN Developer Support: Bill Taylor (btaylor@hayes.com) ISDN Product Literature: Stephanie Lopez (slopez@hayes.com) ISDN Sales: Jon Hendricks (jhendricks@hayes.com) Terminal adapters Motorola UDS 5000 Bradford Drive Huntsville, AL 35805 (205) 430 8000 (voice) PRI ethernet bridges Network Express Andrew Hasley VP, Marketing 2200 Green Road Ann Arbor, MI 48105 (313) 761-5005 (voice) (313) 995-1114 (fax) Multi-protocol router Spider Systems UK France Germany Spider Systems Limited Spider Systems SA Spider Systems Limited Spider House Les Algorithmes Schadowstrasse 52 Peach Street Saint Aubin 91194 D-4000 Dusseldorf 1 Wokingham Gif-sur-Yvette Germany England Paris Cedex RG11 1XH France 0734 771055 (voice) (1) 69 41 11 36 (voice) (0211) 93 50 120 (voice) 0734 771214 (fax) (1) 69 41 12 27 (voice) (0211) 93 50 150 (fax) Handsets Telrad Telecommunications, Inc. 135 Crossways Park Drive Woodbury, New York 11797 (516) 921-8300 1 800 645-1350 --- 13) How about that SPARCstation 10? FYI, the hardware on the SS10 supports 2 B channels (64K+64K) and 1 D channel (16K) for a grand total 144K in marketing speak. On *each* BRI (Basic Rate Interface). The "DBRI" chip in the SS10 supports audio devices and *2* Basic Rate Interfaces. Typically you might use both B channels for data, 1 channel for voice and 1 channel for data, or 1 channel for data to 1 point and 1 channel for data to another point. In some parts of the world it's also popular to run X.25 over the D channel. Info from the SPARCstation 10 full announcement e-mail: - What Becomes Available When: o ISDN Chip on the motherboard Q3 CY92 ISDN Drivers on Solaris 2.x Q4 CY92 Solaris 2.x Teleservices API Q1 CY93 Solaris 2.x Wide Area Networking software Q1 CY93 Solaris 2.x The chip on the motherboard provides a BRI (basic rate interface) ISDN connection that is integrated with workstation audio. The drivers provide a low level interface to the hardware. The Teleservices API enables application development for workstation/telephony integration - providing functions like call setup, transfer, hold, confer, etc. The API is hardware independent so that it will work with third party non-ISDN telephony hardware and software. The WAN software enables data communication - running IP over ISDN (in other words, applications that run over ethernet will run over ISDN). In the first release, Sun will support data communications in the US (for the AT&T 5ESS switch), the UK, France, Germany and Japan. We will support voice services in the US (for the AT&T 5ESS switch) only. dank@blacks.jpl.nasa.gov (Dan Kegel) kessler@Eng.Sun.COM (Tom Kessler) --- 14) Why does certain ISDN TE only work with a specific ISDN switch? In the bad current days before National ISDN-1, the ATT 5ESS switches and Northern Telecom DMS100 switches speak different call setup dialogues. That's why you will see ISDN TE listed as 5ESS, DMS100 or both. Jim.Rees@umich.edu (Jim Rees) jerry@watchman.sfc.sony.com (Jerry Scharf) --- 15) Where can I read more? "ISDN In Perspective" Fred R. Goldstein Addison-Wesley ISBN 0-201-50016-7 "ISDN: Concepts, Facilities, and Services" Gary Kessler ISBN 0-07-034242-3 "ISDN and Broadband ISDN" (2nd edition) William Stallings Macmillan ISBN 0-02-415475-X The 1990 ISDN Directory and Sourcebook Phillips Publishing Inc. 7811 Montrose Road Potomac, MD 20854 (301) 340-2100 ISDN Sourcebook Information Gatekeepers Inc. 214 Harvard Ave, Boston, MA 02134 (617) 232-3111 1 800 323-1088 Bellcore ISDN Availability Report WR-NWT-2102 ($103) 800 521 2673 AT&T Technical Journal special issue on ISDN (Volume 65, Issue 1) January/February 1986 [If anyone can tell me how to get ahold of the next two documents in terms of either ISBN, a publishing company, or an ftp site, I'd appreciate it.] "A subnetwork control protocol for ISDN circuit switching" Leifer, Gorsline, & Sheldon "Multiprotocol Interconnect on X.25 and ISDN in the Packet Mode" Malis, Robinson, & Ullmann EFFector. Issue 2.01, Issue 2.06, Issue 2.08 ftp.eff.org:pub/EFF AT&T Documents -------------- "5ESS(rg.tm) Switch National ISDN Basic Rate Interface Specification - 5E8 Software Release" AT&T document number 235-900-341 "5ESS(rg.tm) Switch ISDN Basic Rate Interface Specification - 5E7 Software Release" {Custom BRI} AT&T document number 235-900-331 "5ESS(rg.tm) Switch ISDN Primary Rate Interface Specification - 5E7 Software Release" AT&T document number 235-900-332 "5ESS(rg.tm) Switch Interface Specification to a Packet Switched Public Data (X.75) Network - 5E8 Software Release" [as in CCITT X.75] AT&T document number 235-900-317 "5ESS(rg.tm) Switch X.75' Intranetwork Interface Specification - 5E8 Software Release" [as in Bellcore's TR-000310] AT&T document number 235-900-325 "5ESS(rg.tm) Switch Documentation Description and Ordering Guide" [list/description of 5ESS documents] AT&T document number 235-001-001 AT&T documents ordering: 1-800-432-6600 USA 1-800-225-1242 Canada +1 317 352-8557 elsewhere AT&T Customer Information Center Order Entry 2855 N. Franklin road Indianapolis, IN 46219 (317) 352-8484 (fax) Northern Telecom Documents -------------------------- NTP 297-2401-100 ISDN System Description NTP 297-2401-010 ISDN Product Guide --- 16) Who do I have to thank for this list? Lots of people, in one way or another. sorflet@x400gate.bnr.ca (Winston WL Sorfleet) Jim.Rees@umich.edu (Jim Rees) PMW1@psuvm.psu.edu (Peter M. Weiss) SYSGAERTNER@cygnus.frm.maschinenbau.th-darmstadt.de (Mathias Gaertner) apsteph@cs.utexas.edu (Alan Palmer Stephens) art@opal.acc.com (Art Berggreen) awillis@athena.mit.edu (Albert Willis) bharrell@garfield.catt.ncsu.edu (Ben Harrell) blsouth!klein@gatech.edu (Michael Klein) cliff@Berkeley.EDU (Cliff Frost) craig@aland.bbn.com (Craig Partridge) curt@kcwc.com (Curt Welch) dank@blacks.jpl.nasa.gov (Dan Kegel) dror@digibd.com (Dror Kessler) dwight@hyphen.com (Dwight Ernest) earle@poseur.JPL.NASA.GOV (Greg Earle - Sun JPL on-site Software Support) eleskg@nuscc.nus.sg (Winston Seah) elitman@wam.umd.edu (Eric A. Litman) etxorst@eos.ericsson.se (Torsten Lif) evans@zk3.dec.com (Marc Evans) glarson@bnr.ca (Greg Larson) goldstein@carafe.enet.dec.com (Fred R. Goldstein) huntting@futureworld.advtech.uswest.com (Brad Huntting) jerry@watchman.sfc.sony.com (Jerry Scharf) jik@pit-manager.MIT.EDU (Jonathan I. Kamens) jms@romana.Tymnet.COM (Joe Smith) kessler@Eng.Sun.COM (Tom Kessler) kevinc@aspect.UUCP (Kevin Collins) keyman@doorway.Eng.Sun.COM (Dave Evans) kph@cisco.com (Kevin Paul Herbert) lmarks@vnet.ibm.com (Laurence V. Marks) paul@suite.sw.oz.au (Paul Antoine) pturner@eng.auburn.edu (Patton M. Turner) rachelw@spider.co.uk (Rachel Willmer) rdavies@janus.enet.dec.com (Rob Davies) rogers@eplrx7.es.dupont.com (Wade T. Rogers) ronnie@cisco.com (Ronnie B. Kon) sanjay@media.mit.edu (Sanjay Manandhar) spike@coke.std.com (Joe Ilacqua) tnixon@hayes.com (Toby Nixon) turtle@newshub.sdsu.edu (Andrew Scherpbier) varney@ihlpf.att.com (Al Varney) wb8foz@scl.cwru.edu (David Lesher)