UTS Architecture for Switched Telephone Networks

UTS Architecture for Switched Telephone Networks

By Stuart Garland, Lucent Technologies

Utility Telemetry Service (UTS) is an application that uses the switched telephone network which provides a nonringing data communications connection between a utility service provider and an end user`s location. The UTS architecture is defined in the Institute of Electrical and Electronics Engineers Standard 1390. The Automatic Meter Reading Association sponsored the committee that wrote the standard. The standard specifies a data communication`s application can be initiated from either the service provider (outbound) or the end user`s (inbound) equipment. In either case, two-way data communications is allowed.

There are two access methods specified. The first is designated as the direct-dial access method which is a standard data call. The second is designated as the central office service unit (COSU) access method which is a telemetry data call. The two access methods produce quite different results. The direct-dial access method (standard data call) provides a ringing access to a device at the end user`s device. The call will be effected by features assigned to the line (i.e., call forwarding). The COSU access method provides a non-ringing access to an end user`s device. The call is unaffected by the features assigned to the line. In both cases, the device is wired in parallel with the end user`s telephone. Also in both cases, the telephone network is capable of supporting analog data communications in the range of 300 to 56 K bits per second.

Let`s understand how these two access methods differ when performing a simple meter reading. The first service example is the utility reading the meter device. When the direct-dial access method is used, a standard data call is made. When the connection is made, all phones on the line are rung. The meter device goes off-hook electrically to establish the connection. If the line were forwarded to another location, the utility call would also be forwarded. When the COSU access method is used, a telemetry data call is made to the central office. The utility gives the destination telephone number and a connection is made to the end user`s line. Since this is a telemetry data call, the phone is not rung and the call is not forwarded, even though the end user`s calls may be forwarded.

Upon receipt of a tone, the meter device goes off-hook electrically to establish the connection. Many subsequent telemetry data calls can be conducted during the one data call between the utility and the COSU. The call forwarding feature is used as an example, but there are many features that can be invoked by the end user, including blocking of calls and service disconnect (financial or vacation).

The second service example is a meter device calling the utility for either meter reading or tamper notification. When the direct-dial access method is used, a standard data call is made. The meter device dials the utility, if not blocked by the end user`s features or if the line has not been turned off (financial) and the meter device is connected to the utility computer. When the COSU access method is used, a telemetry data call is made to the central office. The meter device gives the destination telephone number of the utility and the connection is made. Since this is a telemetry call, the call is connected even if the end user has blocked calls to that number or if the service has been turned off (financial or vacation). Other end user features will not be effected (i.e., auto callback).

When the utility makes a telemetry data call to the meter device and the line is in use, the utility gets a busy signal. If, on the other hand, the end user picks up the phone while the telemetry data call is in progress, the telemetry call is dropped, giving the end user priority for outgoing telephone calls.

Applications Supported

The house picture (see figure) illustrates a multitude of data communications applications. Utility meter reading service has been discussed. The utility can, at a predetermined time (i.e., monthly billing) or at random times (i.e., special reads for moves), call the meter and get current readings. DSM is another service. The utility can call an end user`s water, gas or electric utility using the device and, if necessary, turn it on or off. These are typical functions that can be accomplished by a telemetry data call.

The analog display services interface (ADSI) phone is a new type of telephone. In addition to having several new capabilities, it contains a multi-line display. An ADSI service provider could place a telemetry data call to the phone to place a message on the display or to load new software in the phone while the phone is physically on-hook or unattended. This type of service would be useful if a telephone company wanted to leave a message that the new service you requested has been installed. The telephone company could also update an ADSI telephone with the latest version of software. Services are also being considered that would place subscribed-for-advertising on the display phone at various times of the day. Further services could involve a utility leaving a message such as “rates are changing” or “service will be restored at a specific time.”

A telemetry data call can also be used to deliver a visual message waiting indicator instead of the stutter dial tone in use today. A telemetry data call placed to the smart home will allow all of these pictured applications to be connected to the outside world, enhancing their value and operation.

Service providers can deliver a variety of content and new services using a telemetry data call. Consider the delivery of a copy of the Wall Street Journal at 4 a.m. on your home display or fax machine without ringing any of your telephones. Today, a telephone company can test your service line up to the home entry point. The telephone company can now build a new device to test the connectivity of the line inside your residence.

The telephone company could periodically call this device to insure that your phone line is operational throughout your residence. Proactive remote premises wiring fault detection could now become a reality.

Remember, the UTS is an application which uses the switched telephone network Intelligent Pathway platform that provides a nonringing, nonfeature effecting analog data communications connection. The UTS application is provided over a public switched network. The public switched telephone network is not capacity constrained and is continuously engineered to meet capacity requirements. There is ongoing assigned staff to forecast growth and engineering for the needs of its customers.

Users are not involved in providing the additional capacity. The public switched telephone network is engineered to the highest reliability standards. Central office switches are fault tolerant. In many cases the hardware is duplicated. Software is continuously checking itself to determine if there are any problems. As a result, the Lucent Technologies 5ESS switch currently operates at one and one-half minutes per year of average down time. Central office switches are designed for high-capacity calling volumes.

For example, the 5ESS switch capacity is 1 million plain old telephone service call completions per busy hour. If this is not sufficient, central office switches can grow by adding additional hardware. From the using side, the UTS application is network powered. The UTS operates as easily as making a data call over the switched telephone network. From the network side, the Intelligent Pathway platform provides for the UTS application today.

The UTS application uses the existing analog loops to the residence or business. Existing public telephone service today covers approximately 97 percent of the using public. Lucent Technologies switches serve approximately 110 million of those lines. Other vendors switches cover additional local loops providing for the widest area of in-place service capability. From a software implementation standpoint, the Intelligent Pathway software is already resident in the current Lucent Technologies 5ESS and 1A ESS switches.

Access to the public switched telephone network is provided by a variety of companies. The most well known is the Bell Operating Cos. which extend from one coast to the other. Independent telephone companies fill in where the Bell Cos. does not have coverage. This, however, is not the only source for local phone service. New local access providers are coming into the market place. These competitive access providers see a market opportunity in the local loop market and have made many inroads providing local service.

Application Examples–Future Vision

Vision concepts for future applications of UTS are currently being defined but need standardization and development. The first enhancement for discussion is a device subaddress that is transmitted through the telephone network. This capability would allow a service provider to address a specific device at a given telephone number. For example, if a utility service provider wanted to communicate with a hot water heater on a LAN, that device subaddress would be sent across the network. The gateway would be tone alerted and given the subaddress. The call would not be answered unless the hot water heater was communicating.

The next enhancement would be the addition of a ringing capability. Although this platform is a data feature, the service provider may want to alert the end user of a function just performed or of an emergency condition. Remember, all the end user calls may be forwarded to another location. The telemetry call is not forwarded. Therefore, a utility service provider will be able to contact the end user at home even though all calls were forwarded to another location. Another enhancement covers the emergency notification services area. Volunteer firemen, police personnel or utility personnel need to be called when an emergency occurs. An enhancement to the telemetry feature would be a barge-in capability to complement the previously discussed features.

If the volunteer or family member were on the phone, the utility service provider, with permission, would be able to barge-in and communicate with its emergency service employees. This same capability could be applied to other emergency situations such as flooding or other “must get through” type communications. Near broadcast messaging is yet another enhancement. The telephone network can not perform a broadcast such as in radio but the network can make a lot of phone calls quickly. A broadcast that can take place over a short period of time is what I call near broadcast capability. For this capability, a list of telephone numbers would be stored in the telephone network.

The service provider would inform the telephone network what message to send to a predefined list. The telephone network would then deliver the voice or data message to all designated recipients. A utility example would be a list of telephone numbers along a specific route. The near broadcast message could be to turn on or turn off all devices on that route.


The UTS is an application provided by the Intelligent Pathway switched telephone network platform that is capable of delivering any type of nonringing, nonfeature effecting analog data message. The first applications being implemented today are for meter reading, message displays on smart telephones, and delivery of visual message waiting indicators. The capability is already installed in the current Lucent Technologies 5ESS and 1A ESS switches. Additional technical information and business case information can be obtained from the Intelligent Pathway team.

Author Bio

Stuart Garland joined AT&T Teletype Corp. in 1963 where he has held a variety of development, system and marketing assignments. For the last eight years, he has been involved in the subscriber services planning and requirements organization of Lucent Technologies. Stuart is the primary architect and technical requirements author for the UTS, now known as the Intelligent Pathway platform. Stuart received a bachelor`s of science degree in mechanical engineering from Illinois Institute of Technology and a master`s of business administration degree from the University of Chicago.

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The Clarion Energy Content Team is made up of editors from various publications, including POWERGRID International, Power Engineering, Renewable Energy World, Hydro Review, Smart Energy International, and Power Engineering International. Contact the content lead for this publication at Jennifer.Runyon@ClarionEvents.com.

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