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The Telecom Digest for Mon, 18 Mar 2019
Volume 38 : Issue 77 : "text" format

Table of contents
early fiber systemsEric Tappert
Reps. Ask FCC to Protect C-Band IncumbentsMonty Solomon
Re: T4 and T5 carrier systemsFred Goldstein
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---------------------------------------------------------------------- Message-ID: <df3bee30-b93b-1cd0-bac0-78fdf03f0956@ieee.org> Date: 16 Mar 2019 17:09:16 -0400 From: "Eric Tappert" <tappert@ieee.org> Subject: early fiber systems As a partial response to Fred Goldstein's questions in Saturday's Digest, the first field test of fiber technology in the Bell System was the Atlanta system in 1975. It used fiber to transfer DS-3 signals across the city. The commercial version of this was FT-3 (again using DS-3 signals) and was introduced in 1979. Fiber was used in 1980 to transmit voice, video, and TV from the winter Olympics at Lake Placid. That usage was greatly expanded at the LA Olympics in 1984. The first long distance system was installed between New York City and Washington DC along the NE corridor in 1983, at a much higher rate than DS-3. In 1984 Long Lines was planning/installing about 3300 km of fiber network, again operating well above the DS-3 rate. Based on that history, I would guess that fiber systems became "common" in the mid-80s. More recently transmission and switching systems have migrated to packet based. In fact, AT&T announced a few years ago that they would buy no more circuit based switches (but with 40 year life there are still a bunch of them around...). ------------------------------ Message-ID: <AEE5A5BF-E724-455B-98AD-516A3AA554B6@roscom.com> Date: 16 Mar 2019 01:05:11 -0400 From: "Monty Solomon" <monty@roscom.com> Subject: Reps. Ask FCC to Protect C-Band Incumbents Reps. Ask FCC to Protect C-Band Incumbents Caution against harming cable, broadcast transmissions A bipartisan House Communications Subcommittee duo has called on the FCC to protect incumbents in the C-Band. The C-band is currently used for satellite delivery of cable and broadcast network programming to TV and radio stations, satellite radio services, and cable head-ends. The FCC wants to open it up to wireless broadband to help close the digital divide and promote 5G, both prime directives for the commission. https://www.broadcastingcable.com/news/reps-ask-fcc-to-protect-c-band-incumbents ------------------------------ Message-ID: <b8c0ada5-94c1-5cd7-64e3-63eebc64a4b5@ionary.com> Date: 16 Mar 2019 12:13:39 -0400 From: "Fred Goldstein" <invalid@see.sig.telecom-digest.org> Subject: Re: T4 and T5 carrier systems On 3/14/2019 5:18 PM, Michael Moroney wrote: > > > When things went to fiber, what kind of signalling was used? Was it > digital from the start and similar to the DS1/DS3 signalling? Is > what used now all packets like on a computer LAN? > The earliest fiber systems used the same digital hierarchy as coax, up through DS4. Thus it could use the same muxes and channel banks. SONET (and its European counterpart SDH) was developed in the late 1980s to be more fiber-oriented, and dominated the market in the 1990s. Nowadays Carrier Ethernet-formatted fiber is common, as isochronous (TDM) traffic is a small minority of the total, and there are ways to share the fiber with both. > Also what about Verizon FIOS to a home, do they piggtback the phone/TV on > the IP link, or perhaps the other way around the piggyback the IP on a > TV band like cable companies do? FiOS uses three lambdas. The data is usually GPON, a packetized format. One lambda is upstream GPON, one is downstream GPON, and one is analog RFoG (radio frequency over glass), literally analog cable TV, a GHz or so of bandwidth carrying 6 MHz cable channels, most carrying QAM streams. However, all-digital TV transmission is catching on. I'm not sure if Verizon is going there. Google Fiber did. >> ***** Moderator's Note ***** > >> Lost-in-the-mists-of-time department: IIRC, T5 was never implemented, >> because fiber was being rolled out and there weren't enough coax >> cables. But, I may be wrong: does anyone recall when fiber became >> commonly available? > > I have no idea about "commonly available", but I do remember ads from the > 70s where they show this big fat zillion conductor copper phone cable > being yanked into a conduit, followed by this tiny thin cable with light > coming out of its end, coming back out of the conduit, and ATT boasting > that it could carry many times more phone calls than the copper cable. > Must be early-mid 70s. Later, unless they were merely anticipatory. GTE rolled out the first production telco fiber system ca. 1979, in Santa Monica. AT&T started a bit later. -- Fred R. Goldstein k1io fred "at" ionary.com ------------------------------ ********************************************* End of telecom Digest Mon, 18 Mar 2019

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