case study
Situation
For a major service provider in Canada providing services both as an ILEC and CLEC, DS1 remains a
viable business—not a growth business, but one with a large number of circuits and operating effi-
ciency that helps DS1s remain profitable. Recently, however, demand for DS3 services both to and
beyond the demarc has become a more common service request. For this service provider, finding
solutions for these applications was not the challenge. The challenge was to deploy extended-reach
DS3 solutions today that would not threaten operating efficiency and network reliability as the
number of DS3 circuits in the network grows.
Solution
The service provider’s standards committee selected ADC’s Extend
™
Optical/Electrical Line Extender
solution for applications that require DS3/STS-1 signals over distances up to 15 km (9.375 mi) without
use of repeaters. Where the 900 foot distance limitation prohibits use of copper, the predominant
uses of the Extend solution are as follows: extending DS3 service beyond the demarc within buildings
or multiple buildings in a campus; and delivering DS3 from the central office to the customer site.
The Extend O/E Line Extender is a carrier-class system that includes a rack-mount chassis for up to
24 DS3/STS-1 modules as well as a wall mount chassis that holds one or two DS3/STS-1 module.
Both the rack-mount and wall mount chassis use the same bidirectional, plug-in style DS3/STS-1
module. A/B power feeds support redundant power and full alarm capability. Each module also pro-
vides status LEDs for power, transmit failure and receive loss-of-signal for each channel.
Operationally, the Extend system is a simple product — a factor that greatly appealed to the service
provider in solving distance issues associated with DS3 services. On one end of a circuit, the
DS3/STS-1 module converts an electrical signal into an optical signal for transport over singlemode
fiber. At the far end of the circuit, the DS3/STS-1 module converts the optical signal back to electrical.
One local and one remote module together serve as a dual regenerator to extend the distance of a
single DS3/STS-1 circuit.
Extending DS3/STS-1 Signals
to the Demarc and Beyond
Rack-Mounted Chassis

work. The features that characterize all ADC fiber solutions — including high density, superior cable
management, modularity, and ease of service turn-up — carried over to the Extend O/E Line Extender.
The ADC solution was the preferred product for building reliability and operational efficiency into the
growing inventory of DS3 circuits.
3
Network
Element
DSX
O/E
Line Extender
Singlemode Fiber Optic Cable
up to 15 Kilometers
(9.375 miles)
Network
Element
DSX
O/E
Line Extender
Central Office or High-Rise
Business Office Building
E3/DS3/STS-1 Optical Line Extender Used in Multi-floor
Central Office and Collocation Environments
Network
Element
DSX
O/E
Line Extender
Singlemode Fiber Optic Cable
up to 15 Kilometers
(9.375 miles)