TELECOM Digest Thu, 27 Jan 94 12:04:00 CST Volume 14 : Issue 48 Inside This Issue: Editor: Patrick A. Townson Sprint SONET on the Way (John D. Gretzinger) ITU-TS (CCITT) Automated Mail Interface (Dan L. Dale) Telecommuting Centers in LA (Mike Lanza) Cheap, Practical Notch Filtering and Frequency Shifting Methods (Ho Junya) Telcos Start Warning Customers About New Area Codes (Bob Goudreau) Book Review: "Practical Internetworking with TCP/IP and UNIX" (Rob Slade) Broadcast Paging on Merlin 3070 System (Brian Nunes) Wireless Products Based on IEEE 802.11 (Kevin Tanner) Info on Modems That Provide/Multiplex RS-422 and RS-366 (Mike Foltz) Re: GMSK Modulation Method (Charles Randall Yates) Re: Call Waiting/Three Way Together (Al Varney) TELECOM Digest is an electronic journal devoted mostly but not exclusively to telecommunications topics. It is circulated anywhere there is email, in addition to various telecom forums on a variety of public service systems and networks including Compuserve and GEnie. Subscriptions are available at no charge to qualified organizations and individual readers. Write and tell us how you qualify: * telecom-request@eecs.nwu.edu * The Digest is compilation-copyrighted by Patrick Townson Associates of Skokie, Illinois USA. We provide telecom consultation services and long distance resale services including calling cards and 800 numbers. To reach us: Post Office Box 1570, Chicago, IL 60690 or by phone at 708-329-0571 and fax at 708-329-0572. Email: ptownson@townson.com. ** Article submission address only: telecom@eecs.nwu.edu ** Our archives are located at lcs.mit.edu and are available by using anonymous ftp. The archives can also be accessed using our email information service. For a copy of a helpful file explaining how to use the information service, just ask. TELECOM Digest is gatewayed to Usenet where it appears as the moderated newsgroup comp.dcom.telecom. It has no connection with the unmoderated Usenet newsgroup comp.dcom.telecom.tech whose mailing list "Telecom-Tech Digest" shares archives resources at lcs.mit.edu for the convenience of users. Please *DO NOT* cross post articles between the groups. All opinions expressed herein are deemed to be those of the author. Any organizations listed are for identification purposes only and messages should not be considered any official expression by the organization. ---------------------------------------------------------------------- From: JOHN.D.GRETZINGER@sprint.sprint.com Date: 26 Jan 94 21:22:10-0500 Subject: Sprint SONET on the Way OK, so MCI says they are going to do this some day; well here is the time table for Sprint to have SONET in place. Forwarded message from PC SprintMail: Contact: Jim Bowman (O) 913-967-3675 Gerry Simone (O) 202-828-7423 SPRINT TO PROVIDE SONET ACROSS NORTH AMERICA FOR INTERNATIONAL CARRIERS WASHINGTON, D.C., Jan. 22, 1994 -- Sprint will provide SONET (synchronous optical network) transit service across North America by the end of 1994 for the 31 European and Asian carriers forming a multilateral group, the company told representatives of the group in meetings this week. At that time Sprint's international dedicated transit route through North America will be predominantly SONET, and it will be all-SONET in 1995, when synchronous digital hierarchy -- the international equivalent of SONET -- cables will connect the United States with both Europe and Asia. SONET is the emerging transport standard of the Information Superhighway. It carries vastly larger quantities of traffic than most current transport equipment, at speeds up to 20 times faster. Sprint announced its SONET deployment plan as part of its overall broadband strategy in September 1992, and began deploying SONET equipment on its network in 1993. Sprint's SONET deployment is increasing network capacity for rapidly developing international and domestic traffic loads, moving voice, image, data and video simultaneously over Sprint's fiber-optic network already in place. In addition, Sprint's broadband network architecture, combined with deployment of an advanced form of SONET equipment only now becoming available, provides for unprecedented levels of reliability. Representatives of the multilateral group met with Sprint International officials this week at the company's headquarters outside Washington, D.C., to review progress and to confirm schedules and revenue projections for the next two years of a three-year pact signed last March. By that agreement, the international carriers receive preferred rates and service guarantees for transit of international calls across North America. Sprint's price and performance guarantees are available to all signatory companies of the multilateral group for a period of 25 years, a significant benefit for smaller companies that now can enjoy the same volume pricing and associated benefits previously only available to the largest carriers. The value to Sprint is estimated in the tens of millions of dollars. "The technology and capacity of Sprint's advanced fiber-optic network allows us to provide many services for other carriers, including dedicated transit services for overseas carriers since 1989," said Paolo Guidi, president of Sprint International. "Many of the companies in the multilateral group have been Sprint customers for years, and they already were familiar with Sprint's superior quality," Guidi added. "Now, they will see us take that quality to a speed and performance level as yet unattained by other global carriers." Sprint is a diversified international telecommunications company with more than $10 billion in annual revenues and the United States' only nationwide all-digital, fiber-optic network. Its divisions provide global long distance voice, data and video products and services, local telephone services to more than 6 million subscriber lines in 19 states, and cellular operations that serve 42 metropolitan markets and more than 50 rural service areas. John D. Gretzinger Network Engineer Rockwell Support Team +1.310.797.1187 +1.310.430.1761 (FAX) ------------------------------ Date: Wed, 26 Jan 94 21:53 EST From: Dan L. Dale <0005517538@mcimail.com> Subject: ITU-TS (CCITT) Automated Mail Interface ********** WELCOME TO A TIES AUTO-ANSWERING MAILBOX (TAM) *********** TIES (Telecom Information Exchange Services) is a set of electronic info services of the International Telecommunication Union (ITU) in Geneva, Switzerland. ITUDOC is the TIES electronic document distribution service. For help with the ITUDOC email interface or info on other interfaces (e.g., Gopher), send the line HELP in the message body to this address (itudoc@itu.ch). Include the line GET ITU-5971 for a list of Road Map and Index files. NEWS FLASH: Happy New Year! For concise info on ITUDOC access methods, send the command GET ITU-4313. Note all references to 'CCITT' should be replaced by 'ITU-T'. TAM replied on January 24, 1994 at 7:59 AM local time in Geneva. Access to TAM from Major eMail Service Providers The TIES Auto-Answering Mailbox (TAM) is accessible from several major email service providers. ACCESS FROM MCI MCI users can access the TAM through MCI's facilities for access to other mail systems (EMS). The TAM can be accessed through MCI's Internet gateway. You can then download documents from your MCI mailbox using a file transfer program in your communications package (e.g. Kermit or Zmodem). If you have problems with one gateway, please try the other. ACCESS FROM MCI MAIL VIA INTERNET: 1. At COMMAND, type CREATE 2. At TO, type ITUDOC followed by EMS in parentheses. For example, TO: ITUDOC (EMS) 3. At the prompt EMS: type INTERNET. For example, EMS: INTERNET 4. At MBX: type itudoc@itu.ch. For example, MBX: itudoc@itu.ch 5. At the next MBX: type return to end addressing 6. Complete as usual EXAMPLE MESSAGE The email message below retrieves the Road Map and Index file for the ITU Telecommunication Standardization Sector Group: To: ITUDOC EMS: Internet MBX: itudoc@itu.ch FROM: (NAME) SUBJECT: (IGNORED) START GET ITU-1100 END HOW TO DOWNLOAD DOCUMENTS FROM MCI MAIL: File transfer protocols supported by MCI include - Zmodem - Kermit - Text (MCI account default for downloading ASCII data only) If the document you retrieve from your MCI mailbox is a binary format, you must use either Zmodem or Kermit transfer protocols. 1. Note the number of the message you want to download. 2. At COMMAND, type DOWNLOAD followed by the number of the message you want to DOWNLOAD and the name of the protocol you want to use. For example, COMMAND: DOWNLOAD 3 KERMIT 3. MCI will provide a message that explains how many files are contained in the transfer. You will receive an itemized list of the text and binary message segments contained in each download request. When prompted, enter a filename for each file you wish to download or press return if you wish to skip that segment. Specify a file extension that corresponds to the document type. The TAM always returns two message segments in reply to a GET command. The first message segment part is always in ASCII format and contains information (attributes) of the document (e.g., title, file size and type). The second message segment part is the actual document. You may choose only to download the second message segment which is the actual document. 4. When you have completed assignment of filenames for the messages you wish to download, press return to begin. You may then need to give the command for your communications software to begin the download process. For more complete information, use MCI's HELP DOWNLOAD command. ACCESS FROM COMPUSERVE Compuserve mail users can access the TAM through Compuserve's Internet mail gateway facility. ACCESS FROM COMPUSERVE MAIL VIA INTERNET: 1. Choose COMPOSE a new message, edit the message with TAM commands, then choose SEND 2. At SEND TO (NAME OR USER ID), type >internet:itudoc@itu.ch For example, Send to (Name or User ID): >internet:itudoc@itu.ch 3. At SUBJECT, type any text (TAM ignores subject fields) 4. Complete as usual HOW TO DOWNLOAD DOCUMENTS FROM COMPUSERVE: For complete information, use Compuserve's HELP DOWNLOAD command. ------------------------------ Date: Wed, 26 Jan 94 15:10:07 GMT From: Mike Lanza Subject: Telecommuting Centers in LA Commentators have said that the LA earthquake forces many Angelenos to try mass transit and see if they like it. More importantly, from my point of view, the quake will force many Angelenos to try telecommuting. I'd like to know about the telecommuting centers that exist today in the LA area, and any new plans for such centers in the aftermath of the quake. How many are there? How big? What sort of equipment do they have? Has anyone in government thought about this? How about entrepreneurs? If I were in LA right now, I'd be looking into setting up a telecommuting center myself ... Mike Lanza ------------------------------ From: HO JUNYA Subject: Cheap, Practical Notch Filtering and Frequency Shifting Methods Date: Thu, 27 Jan 1994 02:37:49 -0500 I am looking for cheap and practical ways of filtering a telephone line's usable audio bandwidth into a number of segments or notches (somewhere between 8 and 16 or more?), and multiplying or shifting each segment into a new block of frequencies, (this mapping will be determined beforehand) with as little noise or distortion as practical. (this would theoretically be used to 'scramble' a voice conversation) This is for an engineering design course, where we are to build a working (mostly hardware) model of something unique (or somewhat unique) in one term (about 2.5 months left). An example of what I mean follows: Say the bandwidth to be used is 0Hz - 4KHz, and I will use four segments: 0-1KHz, 1-2KHz, 2-3KHz, 3-4KHz. after filtering out each segment, say my mapping instructions dictate that I should map the segments as such: the 1st to the 4th segment, the 4th to the 2nd segment, the 2nd to the 3rd segment, and the 3rd segment to the 1st segment. (so the original 0-1KHz segment gets shifted to 3-4KHz, the original 3-4KHz segment gets shifted to 1-2Khz, and so on) There aren't really set restrictions on this - (ie, is it easier to shift these segments after converting them from analog to digital signals?) - as long as it would work :-) As an aside, the mapping will be done using a hardware RNG. Any comments or suggestions are most appreciated. Thanks, Junya hojunya@ecf.toronto.edu ------------------------------ Date: Wed, 26 Jan 1994 17:33:23 -0500 From: goudreau@dg-rtp.dg.com (Bob Goudreau) Subject: Telcos Start Warning Customers About New Area Codes In the past, some people have ventured the opinion that the general telephone-using population won't even notice the coming of non-N{01}X area codes in the North American Numbering Plan starting next year. However, there is at least one telco that apparently disagrees. My most recent phone bill included the usual _Southern_Bell_News_ newsletter, which had the following as its uncopyrighed cover story, so I assume that Southern Bell wants to get the word out as widely as possible: WHEN THE NEW AREA CODES ARRIVE, THEY'LL LOOK A LITTLE FUNNY Don't Be Surprised If You Begin Seeing Area Codes That Don't Look Like Area Codes! [In Box:] DON'T LET IT CATCH YOU BY SURPRISE! The area code numbering plan for North America was established in the 1940s, and has lasted nearly fifty years. Because of the phenomenal growth in telecommunications services by pagers, mobile phones, fax machines and telephone lines, the telecommunications industry is running out of area codes. Therefore, a new area code format for North America is being introduced on _January_1,_1995_ [italics in original text]. The new numbering plan will add 640 new number combinations for area codes by using any number (0 through 9) as the middle digit, instead of restricting the middle digit to a zero or one, as the old plan did. Area codes will remain three digits, like 704 in North Carolina. This change makes new area codes available for _future_ use, and will not change your current area code. New area codes will be added, as they always have, when needed to accommodate growth in telephone lines or communications services. The Customer Guide section in the front of your white pages directory contains area code information for the United States. The change to the new numbering plan will not affect your rates for telephone service. It may, however, make recognizing a geographic location based on the area code more difficult. All the phone companies in North America are working together to make this transition orderly, and to try to ensure that all calls go through. ------------------------------- Bob Goudreau Data General Corporation goudreau@dg-rtp.dg.com 62 Alexander Drive +1 919 248 6231 Research Triangle Park, NC 27709, USA ------------------------------ Date: Thu, 27 Jan 1994 05:05:51 MDT From: Rob Slade Subject: Book Review: "Practical Internetworking with TCP/IP and UNIX" BKPIWTAU.RVW 931130 Addison-Wesley Publishing Co. Kelly Ford, Promotion/Publicity Coordinator Heather Rignanesi, Marketing, x340, 73171.657@Compuserve.com P.O. Box 520 26 Prince Andrew Place Don Mills, Ontario M3C 2T8 416-447-5101 fax: 416-443-0948 or Tiffany Moore, Publicity tiffanym@aw.com Bob Donegon bobd@aw.com John Wait, Editor, Corporate and Professional Publishing johnw@aw.com Tom Stone, Editor, Higher Education Division tomsto@aw.com 1 Jacob Way Reading, MA 01867-9984 800-822-6339 617-944-3700 Fax: (617) 944-7273 5851 Guion Road Indianapolis, IN 46254 800-447-2226 "Practical Internetworking with TCP/IP and UNIX", Carl-Mitchell/Quarterman, 0-201-58629-0, 1993 tic@tic.com smoot@tic.com Another good explanatory title. For those who need to connect a UNIX machine to the Internet, this is a one-stop reference for most of the basic necessities. The book starts with a historical and conceptual backgrounder on the Internet. This first section also gives technical and even some programming details on the basic IP, TCP and UDP protocols. The technical level is advanced, but fully explained for the perseverent newcomer. Part two is the practical side. Four chapters give the basics of the setup, email, sendmail and other services. For a standard system, this could be almost all you need to get running. Part three covers advanced topics such as the integration of microcomputers, network management and debugging. It is nice to see a work that addresses the issues of micros, which are ubiquitous in the usual workplace. It is equally nice to see a practical approach, such as the suggestion to use terminal emulation if such will fill the bill. (It is amusing to see a mild tendency towards UNIX chauvinism in such subtle ways as the use of the UNIX default lower case filename convention applied to the case insensitive/upper case MS- DOS file system.) Appendices give tips on the use of various Internet services as well as some useful utility program listings. As always with Quarterman's writings, there are extensive biliographic and reference listings. copyright Robert M. Slade, 1993 BKPIWTAU.RVW 931130 Permission granted to distribute with unedited copies of the TELECOM Digest and associated mailing lists/newsgroups. ====================== DECUS Canada Communications, Desktop, Education and Security group newsletters Editor and/or reviewer ROBERTS@decus.ca, RSlade@sfu.ca, Rob Slade at 1:153/733 DECUS Symposium '94, Vancouver, BC, Mar 1-3, 1994, contact: rulag@decus.ca ------------------------------ From: bnunes@netcom.com (Brian Nunes) Subject: Broadcast Paging on Merlin 3070 System Date: Thu, 27 Jan 1994 11:45:20 GMT Does anyone know how to simultaneously page all stations using a Merlin 3070 system? One of the people in my office did it by mistake once but couldn't remember what she did. When I called AT&T, they told me it couldn't be done, but I know it's possible. Maybe it's undocumented? Does anyone know? =Brian Nunes=*-*-*-*-*-* bnunes@netcom.com -*-*-1-213-656-9117 7985 Santa Monica Blvd. #109-473, West Hollywood, CA 90046-5112 ------------------------------ From: kevin_tanner@wiltel.com Subject: Wireless Products Based on IEEE 802.11 Date: Thu, 27 Jan 94 10:34:10 GMT Organization: WilTel Greetings all... Does anyone out there know of any vendors who are exploring products based upon the IEEE 802.11 standard/ISM Bands/TDMA/CDMA with bandwidth range from 1.2 Mbps to 20 Mbps which can handle both voice and data? Please contact either myself or Aamir Hussain. Thanks in advance. Kevin D. Tanner WilTel, Inc. Kevin's Telephone: (918) 588-5843 Aamir's Telephone: (918) 588-5156 FAX: (918) 588-5616 E-mail: kevin_tanner@wiltel.com ------------------------------ From: mike_foltz@sgate.com Subject: Info on Modems That Provide/Multiplex RS-422 and RS-366 Date: 26 Jan 1994 17:45:49 GMT Organization: Collins International Services Company To all: I am looking for vendor information on modems that provide and multiplex both RS-422 and RS-366 interfaces. The interfaces provide both data and dialing information to be transmitted. I have video teleconferencing and Inverse mux equipment that have the RS-422 and RS-366 interfaces. Our 4 building campus has both fiber optic and copper in its distribution. The modems would be used to remotely connect the video teleconferencing equipment over fiber or copper to the Inverse mux equipment. Thanks in advance, Mike foltz mike_foltz@sgate.com 703-803-8361 ------------------------------ From: yatesc@eggo.usf.edu (Charles Randall Yates) Subject: Re: GMSK Modulation Method Date: 27 Jan 1994 11:08:02 GMT Organization: University of South Florida In article rsinha@iucaa.ernet.in (Sinha) writes: > I am trying to find recent references to GMSK(Gaussian Mean Shift Key) > method of modulation in CDMA type spread spectrum application. Are > there other modulation methods known which are still more efficient > from the consideration of bandwidth utilization? Mr. Sinha, It is my understanding that GMSK stands for "Gaussian Minimum-Shift Keying", which is a variant of MSK ("Minimum-Shift Keying"), which in turn is a variant of FSK ("Frequency-Shift Keying"). In FSK, a signal is modulated between two frequencies which are symmetrical about a center frequency. Call the difference between these two frequencies df. In MSK, df is reduced to the minimum value that will get the job done, which turns out to be half the baud rate (i.e., the symbol rate): df = Tb/2 (where Tb = baud rate). This results in the smallest bandwidth for an FSK signal. I believe that GMSK is simply an MSK modulation scheme coupled with gaussian transmit and receive filters. I am confused by your reference to efficient bandwidth methods for spread spectrum systems since these systems purposely widen the bandwidth greatly. Although I couldn't find anything on GMSK in them, the following references may be of help to you: [1] "Digital Communications and Spread Spectrum Systems", Rodger E. Ziemer and Roger L. Peterson. [2] "Digital Communications", John G. Proakis. I hope this information may be of use to you. Randy Yates Signal Processing/Communications Systems Student University of South Florida, Tampa, Florida ------------------------------ Date: Thu, 27 Jan 94 03:19:04 CST From: varney@ihlpe.att.com Subject: Re: Call Waiting/Three Way Together Organization: AT&T In article izzy@access.netaxs.com (Michael Israeli) writes: >> [TELECOM Digest Editor's Note: Try getting an actual three way call >> installed between CW and 3WC (because flashing the hook could cause >> one thing to hand you a CW at that point in time does your flash mean >> you want to accept the new call or connect the other two. Since maybe >> you do not want that to happen (the two you dialed to be joined >> together) telco has chosen to block CW for that limited period of >> time. Let us know. PAT] > Well, I attempted the following: [deleted excellent test of 3WC/CW interactions.] > So, I placed another call to Bell of PA. I explained again my > situation, receiving a CW tone during a three way call. The agent > looked into some book she had, and explained to me that I live in an > area with a "5E" switching system, in which CW and 3WC can have NO > interaction. Whereas my friend who lives in a different area has a > "1A" switching system, where they DO interact! Well, you probably don't want any excuses or a long history of the pain involved in this area, so here's my nickel summary: 1) The interaction of 3WC and CW evolved over about 5 years in the early 1970s on 1E/1A ESS(tm) switches. Trying to explain the actions of a switch to a customer who only has one input ("flash") at any given point lead to a really elaborate set of somewhat inconsistent modifications to the code, resulting in the current implementation. That implementation works basically as follows -- a) Set up call, flash and place second leg of call. From the moment of flash until the second call has answered, CW will return "busy" to any incoming call. Flash will drop the second call leg. b) After second leg answers, without CW, a flash will drop the second call leg. From the moment of CW alert (the "click" plus tones), a flash will connect to the CW caller, and leave the other two parties talking on your nickel. Another flash (or disconnect by the CW caller) will connect you back to the 3W call. If the CW caller does not disconnect, you can toggle back and forth between 3W and CW calls as frequently as you desire. c) After second leg answers, and CW alert occurs, but you ignore it, and the CW caller abandons the call, there is no 3W call to reach with a flash. But you don't know the caller has abandoned, so the CO "remembers" that you once had CW alert offered and treats a flash as an attempt to reach a CW call anyway (you get reorder, I believe). This failed attempt erases the CW alert "memory", so that future flashes will drop the second leg of the 3W call. d) A side-effect of the "toggle back and forth" of 3W and CW is that, until the CW caller drops off your line, you cannot "drop" the second leg of the 3W call! Try writing that down, along with other interactions. Better yet, try making that a general requirement for all switches, and extend it to other feature interactions, multi-line groups, etc. It's a tough job. That's why 2) Bellcore, in writing generic requirements for switches in the LSSGR, specified a simpler, more easily understood behavior: a) Set-up two legs of 3W call as before. From the point of flashing to set up the second leg UNTIL you flash to drop the second leg, you cannot receive a CW alert -- and callers get a "busy" signal. b) If you drop the second leg, you can now receive CW alert and flash will connect you to the new caller. But until the CW caller drops off of your line, you cannot initiate a 3W call (second leg) -- each flash just toggles you from one call to the other. Much easier to explain to customers, and new switch vendors, than the 1E/1A ESS implementation. That's why the 5ESS(reg. tm) switch acts in this simpler manner -- it's what the TELCO (via Bellcore) specified. {The dime summary would have been half as long :) } > It is a pain that my line is busy during 3WC, because I ordered CW for > the specific reason of NOT loosing calls! Are there any specific > questions I should ask the phone company, or just give up on this one? CW does not alert 100% of the time -- for example, when you pick up the phone and start dialing, CW alerting is blocked. In fact, it will be blocked until your called party answers. Several folks have complained that their CW is "broken" because 1) they receive normal dial tone at the beginning of a call (implying there are no messages), 2) they dial a call and talk for awhile without any CW tones, 3) they go on-hook and then off-hook, only to receive a "messages waiting" interrupted dial tone. Conclusion: CW isn't working!! Fact: They received a call sometime after the first dial tone and before the call was answered, and their incoming call was routed to Voice Mail immediately (no CW). But you do have several options: A) Get a good voice mail system that will get any call where you can't receive the Call Waiting alert. Sometimes CW won't be available with voice mail, and sometimes it will. Either way, callers won't get "busy" during windows when CW is never available, such as during dialing and before answer on any call. If you spend 20 seconds dialing and listening to ringing and only 2 minutes on a call, then callers have a 17% chance of getting busy even without the 3WC problem. B) Ask if a Centrex-like package is available for residential lines. Some TELCOs have these priced in a bundle with Call Hold. Better, if you can, just get the "Call Hold" feature added to your existing features. Call Hold will not interpret "flash" as anything, but will give you dial tone -- from which you can dial a code to "hold" the current call and answer a CW caller or another code to "drop" the second leg of a 3W call. Since you are using explicit codes, the Bellcore restriction of 3WC/CW does not apply, and you can get CW while on a 3W call. (CW will still not work during the time you are dialing and waiting for a call to be answered.) C) Get a second line, with hunting from the first on busy. Avoids the CW blockage during dialing/unanswered-call periods, and you can drop the CW feature. Or retain it and be able to be on 4 calls at once! D) (The one I use.) Get ISDN. Even with 1 CSV B-channel, ISDN can support 3W calls explicitly (push the CONFerence button) and also support alerting of another incoming call (push the new call appearance to answer). You can drop the new incoming call with another button. You can even MERGE the incoming call with your current outgoing call. I'm sure I missed some other ideas ... Al Varney -- just my opinion ------------------------------ End of TELECOM Digest V14 #48 *****************************