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Frequently Asked Questions (FAQS);faqs.124 Q. WHAT ABOUT COPYRIGHT ISSUES? A. Currently, wireless cable systems have assumed that they may use a compulsory license to pay for copyright issues (similar to what cable companies do today). A compulsory license enables systems to re-transmit broadcast signals for a pre-established fee to compensate producers of TV programs. The copyright office recently announced that wireless cable is NOT a cable system, therefore, these systems may not use compulsory licenses. They have decided, though, that wireless cable systems may continue to use the compulsory license for two years (I will try to get an exact date). I have heard of some legislation that may allow small cable companies and wireless cable companies to use a compulsory license for up to 11 years. I don't think that anything has happened with this bill yet, though. Hopefully, there will be more legislation on this point. Q. WHAT IS THE HISTORY OF MMDS? A. It is a fairly new service that developed from MDS (multi-point distribution service) which could only send one or two channels. Originally, the FCC thought MDS would be used primarily to send business data. However, since MDS's creation in the early 70's, the service has become increasingly popular in sending entertainment programming. Because the FCC does not regulate the content of the transmission, alternative uses would not be prohibited. Q. HOW DOES MMDS WORK COMMERCIALLY? A. A MMDS licensee, which is similar to a broadcast station owner, leases transmission time to programmers on a first-come, first-served basis. The programmers, in turn, are responsible for designing and selling their programs to the subscriber. A MMDS applicant can choose to operate as a common carrier. In the telecommunications industry, a common carrier also may provide services such as audio only transmissions, telephone, or data. If a MMDS licensee is currently operating as a common carrier, the FCC requires that the licensee and the programmer not be related or affiliated. A common carrier offers transmission service for hire and cannot control program material or serve primarily its other business interests. A MMDS applicant can alternatively choose to operate as a non-common carrier. This scenario in effect would constitute a non-common carrier wireless cable system. Q. HOW DO I APPLY FOR THE FREQUENCIES? A. First, you should contact the FCC and get the proper applications. This includes the following forms: FCC form 430 - Licensee qualification report FCC form 494 - Application for a new or modified microwave radio station license under Part 21 FCC form 701 - Application for additional time to construct a radio station (Just in case something happens!) FCC form 494A - Certification of completion of construction THE FCC HAS CURRENTLY PLACED A FREEZE ON ALL NEW APPLICATIONS UNTIL THEY CAN PROCESS THE BACKLOG AND SETUP NEW PROCEDURES TO DEAL WITH ALL OF THE NEW APPLICATIONS. They say they were getting about 1,000 applications a month! Q. HOW ARE LICENSEES SELECTED? A. When more than one application using the same E or F group of frequencies is accepted for filing proposing a multichannel MDS station in the same service area, the Commission will use a lottery (random selection) to award a conditional license. Minority preference and/or diversity preference may be claimed by the applicant. The factors used to determine if an applicant qualifies for either type of preference are explained in Section V of FCC Form 346. When more than one application using channel 1, 2 or 2A in the same service area is filed, the Commission will use a comparative hearing to award a conditional license (construction authorization). Charles Gratch, who heads applications processing in FCC's Domestic Facilities Div., said he often tells callers that they don't need a license to enter the wireless cable field; he advises them to find licensees who can't put together a system and try to collect enough channels to start a business, eliminating long and speculative lottery processes. Even with new rules approved by the FCC (TVD Oct 15 p5), challenges to develop wireless cable, particularly if there's an existing cable system, will be formidable, Schmidt said. Wireless cable services also could face increasing competition from satellites, he said. Q. WHAT IS THE RANGE OF WIRELESS CABLE? A. Wireless cable systems usually get a range of 25-30 miles (this depends on the terrain, as the transmitting and receiving antennas must be line- of-site). This may make it feasible in rural areas. Q. WHAT ARE THE COSTS OF A NEW STATION? A. According to a couple of books and magazine articles that I have read, the cost to build a wireless cable station is much less than that of a regular cable system. This is because cables don't have to be strung all over town. In comparison to the cost of cable, a 10-watt transmitter only costs about $17,000. When combined with the antenna structure and monitoring, switching, and originating equipment, it costs about $150,000. (These are 1988 figures and they do not consider the costs for antennas and downconverters). Because of the low initial investment costs, it is possible for wireless cable systems to charge less than their regular cable counter-parts. According to one article in Forbes Magazine, "Since March of last year, Charles Mauszycki's tiny Family Entertainment Network (1989 revenues, $564,000) has signed up 1,200 of Sioux Falls' 8,000 outlying homes for its wireless cable system. Cost:$17.95 a month for basic cable, plus $9.95 a month for Showtime. Mauszycki says that the system, less than one year old, already has positive cash flow." This particular system was set up in a rural farming community that did not already have cable service. Mr. Mauszycki spent about $800,000 to build his system. This is less than $700 per subscriber. The article also mentions that if penetration reached 40%, then the incremental cost of adding the subscribers would bring the cost of the system down to just under $500 per subscriber. To put these figures in perspective, it costs regular cable systems an average of $2,300 per subscriber. (Forbes Magazine, February 19, 1990. "The wireless wonder" by Fleming Meeks) According to the Wireless Cable Association, a complete headend should cost no more than $1.7 million. Usually, you can lower this cost considerably. Q. IS WIRELESS CABLE EQUIPMENT RELIABLE? A. Several excellent manufacturers produce antennas and downconverters for signal reception and decoder boxes that sit on the customer's television which are connected by coaxial cable to the roof antenna. Because the signal is broadcast over the air, it is more reliable than conventional cable and the quality is better than or equal to ordinary cable. Extreme weather conditions do not affect wireless cable's transmitters, so their customers will never experience the outages that are so common in conventional cable. Q. WHAT ABOUT SECURITY? A. Absolute signal security is provided by encoding each wireless cable channel and equipping the converter with a decoding device that responds to a pilot signal carrying a data stream with authorization instructions. Thus, the system is totally addressable. No converter box will have any utility unless it is authorized for service by the central computer. All channels, both Basic and Premium, are hard scrambled. Because the wireless cable system is addressable, it also can accommodate pay-per-view service. Q. HOW ARE WIRELESS CABLE SYSTEMS REGULATED? A. The FCC has specifically preempted local regulation of wireless cable frequencies, asserting that it is interstate commerce. There is no basis for local regulation of the wireless signal. Unlike cable, no public rights of way are used, and all transmission and reception equipment is on private property. Furthermore, the antennas are so similar to regular television antennas that there can be no basis for zoning restriction. Q. WHAT ARE THE BENEFITS OF WIRELESS CABLE TO THE CUSTOMER? A. Availability: Wireless Cable is available to subscribers NOW, whereas traditional cable can't or won't be for years to come. Reliability & Quality: Wireless Cable is not subject to traditional cable's outages or signal degradation. Picture quality is as good or better than coaxial cable. Affordability: Wireless Cable offers affordable programming packages and is priced below or competitively with traditional cable. IN SHORT, WIRELESS CABLE IS THE NEXT GENERATION OF CABLE TELEVISION PROVIDING THE BEST IN SATELLITE CABLE PROGRAMMING, AVAILABLE NOW, AND AT LOWER COST. Q. IS THERE AN INDUSTRY ASSOCIATION? A. Wireless cable operators, license holders, and equipment/service suppliers have formed the Wireless Cable Association. Among its activities the WCA has established a set of industry standards, both business and technical. The WCA has also made the industry's concerns known on Capitol Hill and at Federal agencies such as the FCC, NTIA, OTA and DOJ. Current legislative efforts are focused on securing right of access to programming services. The WCA has also opened channels of communication with organizations such as the National League of Cities, NATOA, MPAA and the Association of State Attorneys General. Q. I SAW ONE OF THOSE 'INFOMERCIALS' ABOUT WIRELESS CABLE. ARE THESE COMPANIES LEGIT? A. While some of these companies may be legit, there are some things that they don't disclose. Because of this, two companies have had temporary restraining orders placed against them. A judge has placed some of the following restrictions on them. 1. They may no longer state that applicants are "virtually guaranteed" of winning a license in the FCC lottery or that most wireless cable licenses are "highly valuable." 2. "There may be substantial delays in the awarding of any MMDS [Multichannel Multipoint Distribution System] license due to the length of time the FCC takes to process MMDS applications and award MMDS licenses." 3. That financing for wireless cable systems is hard to get, "given the relatively new nature of this field of technology and that such financing may require additional funds of the customer's own money as a condition" to obtaining system. 4. Provide a new "Risk Disclosure" statement that applicants must sign before sale is completed. This statement informs applicants, among other items, that any representations of value of systems are opinions and not actual values, that the winner of a MMDS lottery wins only 4 channels and that there may be competition with satellite, VCR, and other media. Temporary Restraining Orders have been placed on, or have been filed against: 1) Applied Telemedia Engineering and Management (A-TEAM) and 2) Applied Cable Technologies (ACT). If you deal with any type of application preparation firm, be very careful and read EVERYTHING. Other companies that MAY be questionable include Communications Engineering Management Services (CEMS), Decaxo Capital, Techno Source, and Western Wireless. These companies have management that were involved in a company selling cellular licenses. This company was forced out of business by the FCC for misleading customers. Other questionable companies include MMDS Technologies, Metro Communications Group, and Tele-Wave Technology. I have not heard anything about any other application preparation firm. Also, take note that there is a freeze on all applications at this time and the FCC is currently changing what type of data will be needed for the application. Also, please note the following public notice issued by the FCC: **************************************************************************** Public Notice - 13244 - May 24, 1991 DOMESTIC FACILITIES DIVISION ADVISORY FOR MULTICHANNEL MULTIPOINT DISTRIBUTION SERVICE APPLICANTS It has come to our attention that application preparation firms are offering settlement opportunities to Multichannel Multipoint Distribution Service (MMDS) applicants as part of their application preparation services. Applicants may not enter into a settlement agreement prior to having their application placed on public notice as accepted for filing. Until an application has been accepted for filing, it may be returned as unacceptable and thus would not be eligible to be included in the lottery for a particular market. An application which is ineligible to be included in a lottery is not eligible to be included in a settlement group and could not be counted towards the cumulative chances awarded to a settlement group. 47 U.S.C. S309(i), 47 C.F.R. S21.33(b). Moreover, each person entering into a settlement group must demonstrate that the MMDS application was filed without the intention of entering into a settlement group. Each individual applicant for MMDS must be the real party in interest of its application. 47 C.F.R. SS21.13(a)(1), 21.33. Any questions may be addressed to Susan Magnotti, Domestic Radio Branch, (202)-634-1773. -FCC- **************************************************************************** Q. WHO DO I CONTACT FOR MORE INFORMATION? A. FCC Common Carrier Bureau Washington, DC 20554 (202) 634-1706 Wireless Cable Association International, Inc. 2000 L Street, NW Suite 702 Washington, DC 20036 (202) 452-7823 --------------- EQUIPMENT: There are several companies that provide equipment and consulting services. If you are interested in this, you may want to pick up the latest copy of The Broadcasting Yearbook or Multichannel News. These can be found at most large libraries. Also, I would strongly suggest calling the FCC and the WCA and ask for more information. --------------- For additions, clarifications, corrections, or if you just have a few questions, please feel free to e-mail me. DISCLAIMER: I have no affiliation with any MMDS, MDS, DBS, ITFS, OFS, Radio, Television, broadcast station, or regular cable system. I am definitely not an expert in any of these areas. I have tried, to the best of my ability, to interpret and relay the most accurate and up to date information. However, I do not guarantee the accuracy of this information as some of my sources may be biased or incorrect. B. J. Catlin . Newsgroups: comp.windows.x.intrinsics,comp.windows.x,news.answers Path: bloom-picayune.mit.edu!enterpoop.mit.edu!usc!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!oboe.cis.ohio-state.edu!ware From: ware@oboe.cis.ohio-state.edu (Peter Ware) Subject: comp.windows.x.intrinsics Frequently Asked Questions (FAQ) Message-ID: <FAQ-Xt_723479548@oboe.cis.ohio-state.edu> Followup-To: comp.windows.x.intrinsics Summary: Answers about the X11 Window System widgets and Xt Intrinsics library Sender: news@cis.ohio-state.edu (NETnews ) Supersedes: <FAQ-Xt_718402537@oboe.cis.ohio-state.edu> Reply-To: ware@cis.ohio-state.edu Organization: The Ohio State University Dept. of Computer and Info. Science Date: Fri, 4 Dec 1992 14:32:40 GMT Approved: news-answers-request@MIT.Edu Expires: Fri, 15 Jan 1993 14:32:28 GMT Lines: 1347 Archive-name: Xt-FAQ Version: $Id: FAQ-Xt,v 1.18 92/12/04 09:29:38 ware Exp $ The X Toolkit Intrinsics F.A.Q A monthly posting This article contains the answers to some Frequently Asked Questions (FAQ) from comp.windows.x about the X Toolkit Intrinsics. To submit questions (preferably with an answer) send email to: ware@cis.ohio-state.edu All code fragments are public domain. Contents 0. Xt Glossary 1. Software Versions 2. Related FAQ's 3. Why does my application core dump when I use signals/alarms/cthreads? 4. How do I use a different visual than the default? 5. Which visual should an application use? 6. Why do only Shell widgets have a Visual? 7. Which visual, depth and colormap do Shells inherit? 8. I've done all the above and I still get a BadMatch error. Why? 9. Why doesn't my widget get destroyed when I call XtDestroyWidget()? 10. How do I exit but still execute the DestroyCallbacks? 11. How do I resize a Shell widget? 12. Why can't XtAppAddInput() handle files? 13. What good books and magazines are there on Xt? 14. What Widgets are available? 15. What alternatives to the Intrinsics are there? 16. How do I pass a float value to XtSetValues? 17. +++How do I write a resource converter? 18. How do I open multiple displays? 19. What changed from R3 to R4 to R5? 20. Where are the resources loaded from? 21. What order are callbacks executed in? 22. How do I know if a widget is visible? 23. How do I reparent a widget in Xt, i.e. XtReparentWidget()? 24. Why use XtMalloc, XtFree, etc? 25. How to debug an Xt application? The "+++" indicates the question needs more of an answer. ---------------------------------------------------------------------- 0. Xt Glossary ---------------------------------------------------------------------- o The Xt Intrinsics implement an object oriented interface to C code to allow useful graphical components to be created. Included with this are classes that provide the base functionality: Object, RectObj, Core, Composite, Constraint, Shell, OverrideShell, WMShell, etc. The terms "Xt" and "Intrinsics" are used interchangeably, however, they are used very precisely to mean a specific library of the X window system. In particular, it does not include the Athena, Motif, OLIT or any other widget set. Without further widgets the Intrinsics are not especially useful. o A widget refers to a user interface abstraction created via Xt. The precise use, is any object that is a subclass of the Core class. It is used loosely to refer to anything that is a subclass of the Object class although these are more accurately called windowless widgets or gadgets. o Xlib is the C interface to the X11 protocol. It is one layer below the Xt Intrinsics. Typically a widget uses relatively few Xlib functions because Xt provides most such services although an understanding of Xlib helps with problems. ---------------------------------------------------------------------- 1. Software Versions ---------------------------------------------------------------------- The following are the latest versions of Xt based software: _____________________________________________________________ Software Version Released Next Expected _____________________________________________________________ X11R4 patch 18 (none) X11R5 patch 17 8/27/92 ?? Athena Widgets (see X11R5) Motif 1.2.1 9/92 ?? OLIT ?? ?? ?? Xtra 2.5 6/15/92 ?? Xw X11R4 (none) Xcu X11R5 (none) fwf 3.2 6/08/92 ?? _____________________________________________________________ ---------------------------------------------------------------------- 2. Related FAQ's ---------------------------------------------------------------------- David B. Lewis (uunet!craft!faq) maintains the FAQ on X. It is posted monthly on comp.windows.x and located on export in contrib/FAQ. Liam R. E. Quin (lee@sq.sq.com) posts an FAQ list on Open Look to comp.windows.x. Jan Newmarch (jan@pandonia.canberra.edu.au) posts an FAQ list on Motif to comp.windows.x.motif. Peter Ware (ware@cis.ohio-state.edu) posts an FAQ list for comp.windows.x.intrinsics; it is on export in contrib/FAQ-Xt. ---------------------------------------------------------------------- 3. Why does my application core dump when I use signals/alarms/cthreads? ---------------------------------------------------------------------- In brief, Xlib, Xt and most widget sets have no mutual exclusion for critical sections. Any interrupt handler is likely to leave one of the above libraries in an inconsistent state -- such as all the appropriate flags not yet set, dangling pointers, in the middle of a list traversal, etc. Note that the ANSI C standard points out that behavior of a signal handler is undefined if the signal handler calls any function other than signal() itself, so this is not a problem specific to Xlib and Xt; the POSIX specification mentions other functions which may be called safely but it may not be assumed that these functions are called by Xlib or Xt functions. The only safe way to deal with signals is to set a flag in the interrupt handler. This flag later needs to be checked either by a work procedure or a timeout callback. It is incorrect to add either of these in the interrupt handler. As another note, it is dangerous to add a work procedure that never finishes. This effectively preempts any work procedures previously added and so they will never be called. Another option is to open a pipe, tell the event loop about the read end using XtAppAddInput() and then the signal handler can write a byte to the write end of the pipe for each signal. However, this could deadlock your process if the pipe fills up. Why don't the Intrinsics deal with this problem? Primarily because it is supposed to be a portable layer to any hardware and operating system. Is that a good enough reason -- I don't think so. Note: the article in The X Journal 1:4 and the example in O'Reilly Volume 6 are in error. ---------------------------------------------------------------------- 4. How do I use a different visual than the default? ---------------------------------------------------------------------- This requires a more complicated answer than it should. A window has three things that are visual specific -- the visual, colormap and border pixmap. All widgets have their own Colormap and BorderPixmap resource; only shell widgets have Visual resources (another questions deals with why shells have a Visual). The default value of these resources is CopyFromParent which does exactly what it says. In the shell widget CopyFromParent gets evalulated as DefaultVisualOfScreen and DefaultColormapOfScreen. When any one of the three resources is not properly set, a BadMatch error occurs when the window is created. They are not properly set because each of the values depends on the visual being used. How to get this to work? There are two parts to the answer. The first is if you want an application to start with a particular visual and the second is if you want a particular shell within an application to start with a different visual. The second is actually easier because the basic information you need is available. The first is a little harder because you'll need to initialize much of the toolkit yourself in order to determine the needed information. /* * Some sample code to start up an application using something other * than the default visual. * * To compile: * cc -g visual.c -o visual -lXaw -lXmu -lXt -lXext -lX11 -lm * * To run: * ./visual -geometry 300x300 -visual StaticColor -fg blue -bg yellow * * you need to move the mouse to get the particular visuals colormap * to install. */ #include <X11/Intrinsic.h> #include <X11/StringDefs.h> #include <X11/Shell.h> typedef struct { Visual *visual; } OptionsRec; OptionsRec Options; XtResource resources[] = { {"visual", "Visual", XtRVisual, sizeof (Visual *), XtOffsetOf (OptionsRec, visual), XtRImmediate, NULL}, }; XrmOptionDescRec Desc[] = { {"-visual", "*visual", XrmoptionSepArg, NULL} }; int main (argc, argv) int argc; char **argv; { XtAppContext app; /* the application context */ Widget top; /* toplevel widget */ Display *dpy; /* display */ char **xargv; /* saved argument vector */ int xargc; /* saved argument count */ Colormap colormap; /* created colormap */ XVisualInfo vinfo; /* template for find visual */ XVisualInfo *vinfo_list; /* returned list of visuals */ int count; /* number of matchs (only 1?) */ Arg args[10]; Cardinal cnt; char *name = "test"; char *class = "Test"; /* * save the command line arguments */ xargc = argc; xargv = (char **) XtMalloc (argc * sizeof (char *)); bcopy ((char *) argv, (char *) xargv, argc * sizeof (char *)); /* * The following creates a _dummy_ toplevel widget so we can * retrieve the appropriate visual resource. */ cnt = 0; top = XtAppInitialize (&app, class, Desc, XtNumber (Desc), &argc, argv, (String *) NULL, args, cnt); dpy = XtDisplay (top); cnt = 0; XtGetApplicationResources (top, &Options, resources, XtNumber (resources), args, cnt); cnt = 0; if (Options.visual && Options.visual != DefaultVisualOfScreen (XtScreen (top))) { XtSetArg (args[cnt], XtNvisual, Options.visual); ++cnt; /* * Now we create an appropriate colormap. We could * use a default colormap based on the class of the * visual; we could examine some property on the * rootwindow to find the right colormap; we could * do all sorts of things... */ colormap = XCreateColormap (dpy, RootWindowOfScreen (XtScreen (top)), Options.visual, AllocNone); XtSetArg (args[cnt], XtNcolormap, colormap); ++cnt; /* * Now find some information about the visual. */ vinfo.visualid = XVisualIDFromVisual (Options.visual); vinfo_list = XGetVisualInfo (dpy, VisualIDMask, &vinfo, &count); if (vinfo_list && count > 0) { XtSetArg (args[cnt], XtNdepth, vinfo_list[0].depth); ++cnt; XFree ((XPointer) vinfo_list); } } XtDestroyWidget (top); /* * Now create the real toplevel widget. */ XtSetArg (args[cnt], XtNargv, xargv); ++cnt; XtSetArg (args[cnt], XtNargc, xargc); ++cnt; top = XtAppCreateShell ((char *) NULL, class, applicationShellWidgetClass, dpy, args, cnt); /* * Display the application and loop handling all events. */ XtRealizeWidget (top); XtAppMainLoop (app); return (0); } ---------------------------------------------------------------------- 5. Which visual should an application use? ---------------------------------------------------------------------- This is a point that can be argued about but one opinion is there is no way for an application to know the appropriate visual -- it has to be specified by the user. If you disagree with this then your application probably falls into the category of always using the default visual or it is hardware specific and expects some particular visual such as 24bit TrueColor with an OverlayPlane extension (or some such). Why? No application runs in isolation. Depending on the way a server allocates resources I may not always want your application to run in TrueColor mode if it is going to mess up my other applications. I may be very upset if it chooses to run in GreyScale instead of PsuedoColor or just monochrome. As an example, on a low end color Sun server there are many different possible visuals: monochrome, 256 entry colormap, static gray, static color, and a 3/3/2 TrueColor. The SGI Iris's offer all the above plus 12 bit TrueColor, 24 bit TrueColor, an Overlay Plane. ---------------------------------------------------------------------- 6. Why do only Shell widgets have a Visual? ---------------------------------------------------------------------- This is strictly by convention. It makes it possible for an arbitrary widget to know that the visual it uses can be found by looking for the shell widget that is its ancestor and obtaining the visual of that shell. A widget can have its own visual resource. If it does, it must have its own realize method to use the visual when it calls XCreateWindow(). You should also make this a resource that can be obtained with XtGetValues() so other widgets can find it. A reasonable value is probably XtNvisual. ---------------------------------------------------------------------- 7. Which visual, depth and colormap do Shells inherit? ----------------------------------------------------------------------