Re: Re: [telecom] T4 and T5 carrier systems

>

> 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.

Reply to
Fred Goldstein
Loading thread data ...

Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.