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Technology Stocks : The *NEW* Frank Coluccio Technology Forum -- Ignore unavailable to you. Want to Upgrade?

To: Frank A. Coluccio who wrote (95)	6/7/2000 11:03:00 PM
From: ftth	Respond to of 46821

Below are some snips from the JOLT paper referenced in post #94. Please excuse any unreadable parts (if any) since it's basically unedited OCR output that I just pasted : (there is much more coverage than what I've snipped. It's a 14 page paper and is a very good source if this topic interests you). Sorry that I can't provide a freebie link to it. ------------ Abstract-As fiber is deployed in the local loop, telecommunications powering becomes a key concern. Recent successes in transporting optical power near the I-W level via optical fiber suggest that it may be possible to operate conventional telephone station sets using electricity derived photovoltaically from light in a fiber. In this paper, we investigate the constraints on optical powering in fiber-in-the-loop (FITL) applications. We assess its applicability for FITL in terms of end-to-end efficiency, loop length, and system cost. To make this assessment, we look at several different optical-powering system architectures and components vis-a-vis their cost-versus-delivered-power capability. We also discuss related issues such as safety and reliability. We believe that this is the first comprehensive endto-end assessment of optical powering from a cost point of view. ================= Recent successes in transporting optical power near the 1-W level over fiber suggest that it may be possible to power fiber terminating equipment optically. ===================== However the amount of power that the local operating company is required to deliver to the customer (per line) is set by federal and national regulations and standards. For example, the standard 500-Type telephone set has typical power consumptions of about 0.15 and 0.23 W, respectively, for the off-hook (talking) and ringing states, but FCC and EIA standards [22], [23] currently specify minimum power deliveries of 0.27 and 1.1 W (5 REN) for these states. To use a telephone in an optical loop, another piece of equipment, the ONU, is required at the end of the loop. This unit performs such necessary functions as signal processing (e.g., optical-to-electrical conversion, multiplexing, and A/D conversion) and provides the traditional "BORSHT" functions locally. These additional functions require additional power. The power demands of a multiple-line ONU are established in Bellcore Technical Reference TR-NWT-000909 (24] (TR909), which sets a maximum baseline power drain of 1.8 W, with incremental drains of 0.18 W, 0.9 W, and 2 W for each line in the ONU that is in the on-hook, off-hook, and ringing state, respectively. With these drains as a guide,. the maximum per-line power that any power system will lx required to deliver for POTS-over-fiber is 3.8 W, the drain for a "single-line" ONU in the ringing state. ----------------------- Some of the acronyms from above: A REN is a "Ringer Equivalence Number" as defined in Section 68.312d of FCC Regulations-Part 68 1231. It is based on the impedance of electromechanical ringers on early telephone sets and the 5 REN requirement is intended to accommodate up to 5 telephone extensions simultaneously. Many modern phones have an impedance of less than 0.4 REN-opening the possibility of a revisit of the 5-REN requirement. BORSHT is an acronym for providing Battery voltage to operate the telephone, Overvoltage protection on the copper wire circuit, Ringing, Supervision to detect off-hook/on-hook condition and dialing, Hybrid for two-way transmission over one wire pair, and Testing functions. This is sometimes now called BORSCHT, including the C for the digital-to-analog Codec function ============================= One alternative to powering the entire ONU optically is to use optics only to power a single emergency telephone at each residence and to use commercial (local) powering for all other functions. Special "low-power" telephones could be used for this "lifeline" service. The optically powered telephone demonstrated by BTL [8]-[10], which required only 0.25 mW while off-hook and 0.3 mW for ringing, probably sets the minimum power requirements for such phones. The power drain of this phone-almost three orders of magnitude less than conventional telephones-is impressive. Although it was a laboratory demonstration-and adapting it to the harsh loop environment could increase its power demands significantly-it serves as a benchmark minimum for fiberin-the-loop powering. The use of emergency and/or nonstandard telephones would raise many regulatory and FITL architecture design issues, and could preclude backward compatibility of the telephone system [25] (a feature almost as sacrosanct as uninterruptable service). Another alternative is to use optical power to tricklecharge batteries in a locally powered ONU. This would provide almost infinite battery carryover and thus provide the required uninterruptable service. In this alternative, the optical system would have to deliver enough power to compensate for battery-system conversion inefficiencies in addition to the average drain during the power outage; however, the batteries allow load leveling, which can significantly reduce the instantaneous power demand on the system