{"id":320,"date":"2020-08-18T19:23:47","date_gmt":"2020-08-18T20:23:47","guid":{"rendered":"http:\/\/www.linux-tutorial.info\/?page_id=77"},"modified":"2020-08-22T19:26:02","modified_gmt":"2020-08-22T20:26:02","slug":"this-is-the-page-title-toplevel-155","status":"publish","type":"page","link":"http:\/\/www.linux-tutorial.info\/?page_id=320","title":{"rendered":"ISDN"},"content":{"rendered":"\nISDN<\/title>\n<p>\nFor most of the life of electronic\/electrical communication, the primary method of communication\nhas been the telephone. As a result, there exists a <glossary>network<\/glossary>\nof cables and connection throughout the\nworld that dwarfs the Internet in both number of connections and miles of wire. Wouldn’t it be\nwonderful if we could take advantage of the already existing network? Well, we can. This comes to us\nin the form of a system called Integrated Services Digital Network, or <glossary>ISDN<\/glossary>.\n<\/p>\n<p>\nISDN is one of\nthe fastest growing technologies, particularly in Europe. Local telephone companies are offering it\nas a replacement (or addition) to conventional telephone lines. Until recently, the German phone\ncompany was offering cash incentives for businesses and private individuals to switch to <glossary>ISDN<\/glossary>.\n The\nprimary benefit (at least to most end users) is that you can simultaneously send data across the\nsame lines as your phone. For example, while you are speaking to a customer, you can be faxing them\nthe spec sheets on your latest product <em>across the same phone line<\/em>. Although such\nfunctionality for both partners requires <glossary>ISDN<\/glossary>\nconnections on both ends, your phone could be talking\nto their conventional phone and your fax could be talking to their conventional fax. However, from\nyour office to the phone company is a single telephone connection.\n<\/p>\n<p>\nIf both sides are using\nISDN, they need to be communicating in a fashion similar to a <glossary>network<\/glossary>\n(like with TCP\/IP or IPX\/SPX).\nTherefore, both sides know who is calling. Image getting a call from a customer and having your\ndatabase automatically call up the record on that customer, even before you pick up the phone! This\nability to integrate all these different services from voice to fax to data communication gives ISDN\nits name.\n<\/p>\n<p>\nThe key concept in <glossary>ISDN<\/glossary>\nis the idea of a digital data <glossary>pipe<\/glossary>\nbetween the end device\nand the service provider. Note that I didn’t say between the two participants. This allows the\nservice provider (the phone company) to switch between the <glossary>ISDN<\/glossary>\nconnection on one side to the analog connection on the other. At the receiving end (your office) will\nbe something similar to a switch box. As the packets come in from the service provider, this switch box\nwill <glossary>route<\/glossary> the packets to the\nappropriate device. Each device is set with a particular ID number. This works conceptually the same way as <glossary>SCSI<\/glossary> IDs.\n<\/p>\n<p>\nAs of this writing, three types of connections have been standardized. The\nfirst is often referred to as the “basic” rate as it provides the necessary service for basic users\nsuch as homes and small businesses. This provides two 64 kbps channels for voice or data and one\nchannel for “out-of-band” signaling. In some cases, you could use these two channels simultaneously\nand get 128 kbps. However, this would be considered two phone calls.\n<\/p>\n<p>\nThe “primary” service\nprovides 23 voices or data channels, instead of just two. In Europe, this is increased to 30\nchannels. The third type provides a 4 KHz analog phone channel along with a 8 or 16 kbps data\nchannel. This allows you to use your old analog phone along side the new <glossary>ISDN<\/glossary>\ndevice.\n<\/p>\n<p>\nISDN\nis not just for data communication. As I mentioned the German phone company subsidized the transfer\nfrom the old analog system to <glossary>ISDN<\/glossary>.\n I have an ISDN connection at home. Using the same wires as my\nold phone line, the <glossary>ISDN<\/glossary>\nline comes into a telecommunications box, which converts the signal so that\nmy normal analog phones can work.\n<\/p>\n<p>\nISDN support is provided by isdn4linux, which is a set of\nkernel modules. The main module (isdn) communicates with the driver for the particular card. As of\nthis writing, there is a limited number of cards that are supported. However, many cards are\nsupported that don’t have “official” drivers for them. For example, the AVM A1 (Fritz) card\nis supported using the Teles driver. For more information, check out the \/pub\/isdn4linux directory\non <i>ftp.franken.de<\/i>. This not only has many of the drivers, but also a <i>very<\/i> extensive\nFAQ.\n<\/p>\n<p>\nIf you have a 2-0 or later <glossary>kernel<\/glossary>,\n then you are in luck. <glossary>ISDN<\/glossary>\nsupport is included by\ndefault. When you run ‘make config’, you are prompted to incldue\/activate it along with several different\noptions. There are only a few cards mentioned by name. However, I know that many other cards will work\nwith the drivers that are included.\n<\/p>\n","protected":false},"excerpt":{"rendered":"<p>ISDN For most of the life of electronic\/electrical communication, the primary method of communication has been the telephone. As a result, there exists a network of cables and connection throughout the world that dwarfs the Internet in both number of … <a href=\"http:\/\/www.linux-tutorial.info\/?page_id=320\">Continue reading <span class=\"meta-nav\">→<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-320","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/320","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=320"}],"version-history":[{"count":1,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/320\/revisions"}],"predecessor-version":[{"id":595,"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=\/wp\/v2\/pages\/320\/revisions\/595"}],"wp:attachment":[{"href":"http:\/\/www.linux-tutorial.info\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=320"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}