Signature device for home phoneline network devices

14 Pages·2013·1.04 MB·English

US006535580B1
United States Patent
(12) (10) Patent N0.: US 6,535,580 B1
Strauss et al. (45) Date of Patent: Mar. 18, 2003
(54) SIGNATURE DEVICE FOR HOME OTHER PUBLICATIONS
PHONELINE NETWORK DEVICES International Preliminary Examining Authority, PCT Writ
(75) Inventors: Steven E. Strauss, Ore?eld, PA (US); ten Opmlon’ Aug' 3’ 2001'
John T_ HOHOWaY, Atherton, C A (Us); Primary Examiner—Rexford Barnie
Jason A]exander Trachewsky, P2110 (74) Attorney, Agent, or Firm—William H. Bollman
Alto, CA (US); Lixi Wu, San Jose, CA (57) ABSTRACT
US
( ) Signature apparatus and techniques that make home net
(73) Assignee; Agere Systems Inc” Allentown, PA working devices, e.g., in-Home Phoneline Network (herein
(Us) referred to as “HPN”) devices, isolation ?lters, network
interface devices, etc., detectable by commercially available
( * ) Notice: Subject to any disclaimer, the term of this metallic 100p termination (MLT) test equipment The inven
patent is extended or adjusted under 35 tion also provides a method of testing a telephone line for the
U30 154(k)) by 112 days_ existence of a signature circuit identifying a home network.
The home network signature circuit includes a series com
bination of a voltage breakdown device (e.g., Zener diodes)
(21) APPL No: 09/606,157 and an impedance (e.g., 200K ohm resistor). In operation,
the home network signature circuit shunts the tested sub
(22) Filed; J 1111, 29, 2000 scriber line loop with a voltage-dependent impedance in the
presence of an appropriate test voltage exceeding 80 volts.
Rehted U_S_ App?cation Data Different high voltage thresholds of the voltage breakdown
(60) Provisional application NO_ 60/145,737’ ?led on 1111_ 27’ portion and/or different resistance values of the shunt imped
1999, and provisional application No. 60/172,163, ?led on ance can be implemented in the home network signature
D60 17: 1999- device to produce uniquely detectable signatures. In this
(51) Int. c1.7 ............................................... .. H04M 1/24 Way, itfishpossible to rliIélotffly difffilrentiate between vfa?ious
_ _ types 0 ome networ ev1ces 1 t e various types 0 ome
(52) US' Cl' A; network devices include known voltage thresholds and/or
_ ' ’ ' ’ ' ’ ' shunt impedances. Loop quali?cation for services such as
(58) Fleld 0f Search .............................. .. 379/2203, 24, VDSL Could include an automated remote Scan from a
379/26~01> 26~02> 27~01> 27~03> 27~04> 29~01> central office for home network signature devices being
27~05> 29~11> 93~09> 93~11> 1~03> 1~04> 2 served by telephone lines, e.g., existing in the same binder.
To sense each of the parallel connected home network
(56) References Cited signature devices, the test equipment may preferably be
made sensitive to the threshold voltage, not to the shunt
impedance. The home network signature circuit may simply
U'S' PATENT DOCUMENTS reside between the tip and ring on an HPN adapter. The
4,350,849 A 9/1982 Ahuja home network signature circuit is preferably functional
4,388,501 A 6/1983 Ahuja whether or not the network device is powered up. The home
network signature circuit, in response to the activation
(List continued on next page.) energy signal exceeding a predetermined threshold above 80
volts, will drive an appropriate current back onto the tele
FOREIGN PATENT DOCUMENTS phone line
GB 2 256 332 12/1992 35 Claims, 6 Drawing Sheets
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US 6,535,580 B1
Page 2
US. PATENT DOCUMENTS 5,848,150 A * 12/1998 Bingel ...................... .. 379/399
6,301,227 B1 * 10/2001 Antoniu et a1. ............. .. 379/29
4,807,277 A * 2/1989 Perry ------------------------ -- 379/29 6,301,337 B1 * 10/2001 SChOltZ e161. .............. .. 379/27
4,852,145 A * 7/1989 Bevers 9t 91- -- 6,389,110 B1 * 5/2002 Fischer et a1. ........... .. 379/1.04
5,357,556 A * 10/1994 Dresser ..................... .. 379/27
5,483,573 A 1/1996 Steenton et a1. * cited by examiner
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US 6,535,580 B1
1 2
SIGNATURE DEVICE FOR HOME In particular, as shown in FIG. 5, where the subscriber
PHONELINE NETWORK DEVICES loop pair is combined with other pairs into a cable, the
potential exists for crosstalk into an adjacent pair. For
This application claims priority from US. Provisional instance, where adjacent pairs in a binder group carry VDSL
services, and the downstream VDSL signal overlaps the
Appls. No. 60/145,737, ?led Jul. 27, 1999, entitled “Home
Networking Devices With Signature Circuit”, and No. HPN band, an HPN signal may appear as crosstalk in the
receiver of the VDSL modem.
60/172,163, ?led Dec. 17, 1999, entitled “Signature Device
Since the frequency plan for VDSL is not yet established,
For “In Home Phoneline Networking Transceivers”, the
it is dif?cult to de?nitively estimate the impact of HPN on
entirety of which are expressly incorporated herein by
VDSL. The severity and frequency of occurrence of such
reference. 10
potential crosstalk is highly dependent on many variables,
not yet accurately captured in deployment models. While
BACKGROUND OF THE INVENTION
further study may be required in this area, analysis per
1. Field of the Invention formed to date indicates that the probability of interference
into the VDSL service by HPN terminals does exist at least
The invention relates generally to the ?eld of networking.
15
More particularly, it relates to the ?eld of home networking, in some instances.
as employed in coupling electronic devices to each other, It is widely believed that the primary technical solution to
such as via home telephone lines. VDSL-HPN crosstalk is the installation of a Network Iso
lation Filter (NIF) between the premises wiring and the
2. Background
outside subscriber loop. Such a ?lter blocks transmission of
Home Networking is a new segment of the networking 20 signals at 4 MHZ and higher, but would pass signals under
marketplace that is poised for rapid growth. Achieving the
4 MHZ (providing for POTS, ISDN and ADSL).
goals needed to make home networking a market success is
FIG. 6 shows the use of a network isolation ?lter (NIF) on
a challenging task, however. The nascent home networking
a subscriber loop (i.e., telephone line) installed at the cus
market growth will depend on the emergence of high-speed
tomer’s premises.
broadband access as a catalyst as well as on the availability 25
One of the difficulties faced by service providers before
of robust, low cost, easy to install standardiZed home
networking equipment. Technical analysis has demonstrated they can install a network isolation ?lter or other device to
correct a problem is in identifying the source of a problem
that there is little system margin available for achieving the
in response to a customer’s complaint, e.g., a complaint that
desired rates and robustness if a trouble-free consumer
a subscriber’s VDSL services are not operating correctly. As
experience is desired. To enrich the consumer experience it 30
a result, numerous test and fault isolation systems have been
is critical to consider mechanisms in the system that can be
developed for testing the operability of various components
employed to support simple to use remote diagnostic tools in
in the telephone network to determine if the problem resides
these emerging systems.
in the customer premise equipment (CPE), in the line drop
Home networking utiliZes the telephone wiring within a
connecting the CPE to the switching system, or elsewhere in
household as a communication cable for use by networked 35 the telephone network system. These test and fault isolation
devices within the home (e.g., a computer to a printer).
systems are readily available to telecommunication service
However, the same inside telephone wiring may simulta providers.
neously carry several categories and/or types of signals,
For instance, in one test technique described by the Home
analog and/or digital in a frequency division multiplexed
Phoneline Networking Alliance (“HPN”) 1.0 and 2.0
(FDM) topology. For instance, a single telephone line may 40
speci?cations, a PSD mask that extends from 4 to 10 MHZ
be used to carry plain old telephone service (POTS), ISDN,
is used. HPN signals are imposed by the test equipment on
and/or xDSL services such as ADSL and/or VDSL.
the existing telephone wiring inside a dwelling or office, and
FIG. 4 shows a spectrum utiliZation of POTS, HPN, and are used for local communication between HPN stations.
various xDSL services arranged in a frequency division
multiplexed topology. 45 It is important to consider that the emerging “in-home”
networking technology is being targeted as a consumer
In particular, as shown in FIG. 4, Plain Old Telephone grade service. As such, any design goals must consider the
Service (POTS) exists in the 0—4 kHZ region, xDSL service “technology challenged” consumer and require “out of the
is present from 25 kHZ to approximately 2.2 MHZ box” functionality. In the case of “in-home” networking via
(depending on the de?nition of “x”), and the Home Net existing telephone cable (HPN), the expectation from the
working spectrum occupies 5.5—9.5 MHZ for HPN V1.x consumer simply is that the technology will function prop
technology and 4.75—9.25 MHZ for the emerging HPN V2 erly and require little more than installing a telephone cable
technology. The spectral allocation for the VDSL services is into an available telephone jack in the home. Furthermore,
not yet established but it is expected to use the 26 kHZ to 12 it is typically expected that the technology will provide a
MHZ region. The HPN signals occupy a spectrum which is 55 path to install upper level protocols and drivers with no
higher in frequency than POTS, ISDN, ADSL and VDSL. network con?guration, required by the consumer. This
Although HPN communications are not intended for model obviously assumes that no “truck roll” occurs requir
locations outside the customer’s premises, some level of the ing an in-home service call by a quali?ed service technician.
HPN signal may be present on the subscriber loop pair (i.e., HPN devices can be used without prior installation of a
telephone line) that services the premise’s telephone wiring. 60 NIF. HPN technology has been designed to be robust in the
Normally this does not cause a problem to the telephone face of noise coupled into the premises wiring from the
company because the HPN signal is almost always attenu subscriber loop, such as Amateur Radio Service RFI,
ated below the ambient noise ?oor before reaching the crosstalk from adjacent loops with other HPN devices, and
central of?ce (CO) end of the subscriber loop. even crosstalk from VDSL. HPN operation is optimiZed,
FIG. 5 shows the source and existence of cross talk 65 however, with the provisioning of a NIF. However, the
between an HPN signal and a VDSL signal in a common average consumer can not be expected to install the NIF
binder. within the residence.
US 6,535,580 B1
3 4
There are likely to be several situations that will result in to as “HPN”) devices, detectable by commercially available
NIFs being successfully introduced: metallic loop termination (MLT) test equipment. While the
1) Installation on the subscriber’s line of broadband access disclosed embodiments relate speci?cally to HPN devices in
services such as ADSL or VDSL that employ a splitter particular, the principles of the present invention relate
(which also functions as a NIF). generally to all home network devices utiliZing spectrum
2) Provisioning with alternate POTS services that derive a above that used by ordinary telephone service (i.e., above 4
local POTS interface for the premises wiring from a kHZ) on telephone wiring in a home or small of?ce.
broadband gateway or network termination unit. The present invention enables telephone operating com
3) Telephone operating company installation of an NIF to panies to put in place simple, effective test identi?cation,
remediate VDSL interference as part of ongoing loop isolation and maintenance procedures using existing
plant maintenance procedures. This may be accomplished in-premises cable plant equipment to ef?ciently identify and
with an “add-on” NIF ?lter, or via upgrade of the sub upgrade appropriate subscriber lines which support home
scriber’s NID with one that has been designed with an networking devices (e.g., HPN devices) having one or more
integrated HPN NIF. signature circuits connected thereto, in accordance with the
In any event, it is preferred that the consumer need not 15 principles of the present invention. For instance, subscriber
install an NIF ?lter themselves. To this end, there is a need lines supporting home network equipment identi?ed manu
for apparatus and techniques which allow a telephone com ally by a telephone technician, or automatically using scan
pany to detect, isolate, and correct effects of home network equipment at a central of?ce, may be scheduled for a
ing on the telephone system. technician to install an appropriate network isolation ?lter
(NIF).
SUMMARY OF THE INVENTION
The test may be performed from a suitable location on site
In accordance with the principles of the present invention, or remote from the customer premises. For instance, the test
a home network telephone line signature circuit comprises a may be performed from a remote location such as from a
voltage breakdown element having a breakdown in excess of central of?ce (CO) facility, from a local but non-invasive
80 volts. An impedance is placed in series with the voltage 25 location such as from the junction box outside a customer’s
breakdown element. The voltage breakdown element and premises, and/or from a telephone jack inside the customer’s
the impedance are adapted for placement in series across a premises.
telephone line supporting a home network. The invention also provides a method of testing a tele
A method of indicating a presence of a home network phone line for the existence of a signature circuit identifying
device on a telephone line in accordance with another aspect a home network. The disclosed test is performed over
of the present invention comprises sensing a voltage level of ordinary telephone line interfaces.
an injected energy signal on the telephone line. If the sensed In an ideal world, perhaps all telephone lines would be
voltage level exceeds at least 80 volts, a shunt impedance is out?tted with a network interface ?lter. However, it may be
activated across the telephone line. impractical to rebuild the entire loop plant with NIFs.
35
Rather, it is preferred that only those subscriber lines that
BRIEF DESCRIPTION OF THE DRAWINGS have home network (e.g., HPN) technology be targeted,
Features and advantages of the present invention will and/or only those subscriber lines that co-exist with an
become apparent to those skilled in the art from the follow affected service such as VDSL in the same binder pair be
ing description with reference to the drawings, in which: targeted, to result in manageable maintenance operations.
Needless to say, identi?cation of subscriber lines supporting
FIG. 1 shows a home network signature circuit utiliZed
home networking is potentially a valuable marketing tool for
within a customer premises, in accordance with the prin
Local Exchange Carriers (LECs) that offer other services,
ciples of the present invention.
e.g., broadband residential services.
FIGS. 2A and 2B show signature circuits used for broad
Generally speaking, the identi?cation of those telephone
band services (e.g., ADSL) for a central office splitter (FIG. 45
lines used to support a home network (e.g., an HPN) can be
2A) and a remote splitter (FIG. 2B), as proposed for ADSL
accomplished in one of two ways: using a manual or
POTS splitters in Annex E.1.7 of the T1.413 speci?cation.
automated registration procedure, and/or using a test signa
FIGS. 3A and 3B show exemplary DC home network
ture circuit in one or more home network device.
signature circuits that can be used, e.g., in the front end of
In particular, a telephone line having a home network
an HPN transceiver, in accordance with the principles of the
(e.g., an HPN) established thereon can be identi?ed using a
present invention.
manual, on-line (or other type) registration procedure that
FIG. 4 shows a spectrum utiliZation of POTS, HPN, and develops a database of subscriber phone numbers (and thus
various xDSL services arranged in a frequency division
telephone lines) that have a home network installed. An
multiplexed topology.
55 on-line registration service may even link the more sophis
FIG. 5 shows the source and existence of cross talk ticated user to information about home networking that will
between an HPN signal and a VDSL signal in a common motivate the user to take appropriate action themselves to
binder. improve their service experience, e.g., by installing an NIF
FIG. 6 shows the use of a network isolation ?lter (NIF) on themselves.
a subscriber loop (i.e., telephone line) installed at the cus Alternatively, in accordance with the principles of the
tomer’s premises. present invention, a signature circuit may be implemented in
one or more home network device, or otherwise connected
DETAILED DESCRIPTION OF ILLUSTRATIVE
to the relevant telephone line which supports a home net
EMBODIMENTS
work. If the signature circuit is installed within a home
The present invention provides identifying or signature 65 network device, the signature circuit is preferably functional
apparatus and techniques that make home networking whether or not the network device is powered up. The
devices, e.g., in-Home Phoneline Network (herein referred signature circuit may be connected to the relevant telephone