The AT&T

AT&T

AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...

 (also Lucent, now Avaya

Avaya

Avaya Inc. is a privately held computer networking, information technology and telecommunications company that is a global provider of business communications systems. The international head quarters is in Basking Ridge, New Jersey, United States...

) Merlin telephone system was introduced in late 1983, branded American Bell Merlin. After the breakup of AT&T in 1984, it was rebranded AT&T Merlin. It was designed at the beginning of the 1980s prior to the Bell System Divestiture

Bell System divestiture

The Bell System divestiture, or the breakup of AT&T, was initiated by the filing in 1974 by the U.S. Department of Justice of an antitrust lawsuit against AT&T. The case, United States v...

 as a modern electronic replacement for the dated electromechanical 1A2 Key System

1A2 Key System

The 1A2 Key System is an analog multiline business key telephone system. Unlike more modern multiline systems, every telephone line serving a particular phone is wired into that phone, and electromechanical switches switch the lines in the phone itself...

. Earlier Bell attempts at an electronic key system, such as the Horizon and Dimension, were not as successful as they were much larger systems, in fact the Dimension was a PBX. The Merlin was the first small electronic system, replacing the Com Key 416. The Merlin system was originally sold in 2-line, 6-telephone (206), 4-line, 10-telephone (410), and 8-line, 20-telephone (820) configurations. Later, there was a further 10-line, 30-telephone configuration, with an expansion KSU allowing the system to accommodate up to 70 telephones available (1030 and 3070 respectively).

Predecessors

The 1A2 Key Telephone System

Key telephone system

A business telephone system is any of a range of a multiline telephone systems typically used in business environments, encompassing systems ranging from small key systems to large scale private branch....

 had the following problems which the Merlin System sought to solve:

• Complex electromechanical line switches in every telephone
• Each individual line pair plus control and light pairs must be run to each individual telephone, making for expensive on-premises wiring
  On-premises wiring
  In telecommunication, on-premises wiring is customer-owned communications transmission lines. It is also called customer premises wiring . The transmission lines can be metallic or optical fiber, and may be installed within or between buildings.Premises wiring may consist of horizontal wiring,...
  
  
• Telephones used point to point wiring which had to be hand assembled
• Control units consisted of many separate components including a power supply, line and feature module carrier, and punchblocks
• The above points made manufacturing and maintaining the system very expensive, especially by the 1980s
• Other than line switching, intercom, and hold, there was little possibility for modern features

History

The Merlin fixed these problems by:

• Having line switching done completely electronically at the Control Unit
• Using 4-pair wiring (two digital switching, one for analog and one for intercom)
• Telephones are now made with printed circuit boards and assembly is automated
• Fully electronic, all inclusive, one piece control unit
• Economical to produce and operate
• Slots for feature modules made possible features such as Speed Dialing, Automatic Line Selection, and Redial
• The Merlin telephones were also backwards compatible to the higher end enterprise systems, such as then System 75 and System 85 systems, then later Definity system, now called Communication Manager platforms.

The original Merlin was replaced with the Merlin Plus system in the late 1980s, using circuit cards to be expandable to 8 lines and 20 telephones, much like the original 820 model. The original Merlin Plus was dubbed the 820d. It was identical in features to the earlier Merlin 820 with the Feature Package 2 cartridge installed. Following the 820d was the 820d2. The 820d2 included the previous features as the 820d but featured an Automatic System Access (ASA) processor coupled with a voice synthesis capabilities and a Busy Buster. The ASA processor provided users with call forwarding, direct extension dial, and system answer capabilities. The busy buster allowed users to have the 820d2 automatically retry a busy number every minute for up to 10 minutes and notify the user when the call was connected. Both the ASA and Busy Buster required a their own voice terminal port to function. In the early 90s the Merlin II and Merlin Legend debuted with even more features and expandability, and new MLX telephones, but the system was also backwards compatible with the original Merlin telephones.

In 1999, Lucent Technologies

Lucent Technologies

Alcatel-Lucent USA, Inc., originally Lucent Technologies, Inc. is a French-owned technology company composed of what was formerly AT&T Technologies, which included Western Electric and Bell Labs...

 introduced the Merlin Magix as the replacement for the Merlin Legend. The Magix's carrier was metal and, as such, modules were not encased inside plastic shells as they were with the Legend. The Merlin Magix supported new 4400 series digital telephones as well as older MLX telephones, but it did not support the old ATL series telephones.

Due to declining sales and the introduction of the IP Office product line, Avaya

Avaya

Avaya Inc. is a privately held computer networking, information technology and telecommunications company that is a global provider of business communications systems. The international head quarters is in Basking Ridge, New Jersey, United States...

 retired the Magix on April 1, 2006.

The Partner system succeeded the small end of the Merlin system (206, 410 and 820) in the early 1990s. The final version of the Partner system, the Partner ACS, was introduced in 1990. Due to problems securing parts from distributors and the introduction of the Partner version of the IP Office, Avaya ended production of the Partner ACS on November 8, 2010.

Despite being over two decades old, the Merlin's modern electronic features and legendary Bell System era quality and durability still make the Classic Merlins very popular telephone systems with small businesses.

Cartridge Type I

Feature Package 1 (Available for use in Classic Merlin 206, 410 only):

• 5-party conference calling
• Ringer options
• Prevents outgoing calls on individual phones
• Privacy
• Automatic outside and intercom dialing
• Last number redial, automatic line selection, do not disturb
• On hook dialing, call transfer, hold reminder, group listening

Feature Package II (Included same features as Feature Package I plus the following)

• Personal and system wide 3 digit speed dialing
• Personalized Ringing
• Call pickup
• Group paging zones

Cartridge Type II

Music On Hold

• Allows a music source to be connected to the KSU which is heard by a caller on hold

Music On Hold/Paging

• Allows a music source to be connected to the KSU which is heard by a caller on hold
• Provides a paging system connection and music on hold to be used as background music while no pages are being made.

Cartridge Type III

Power Failure/Extra Alert

• Provides two RJ-11 jacks for standard touch-tone or rotary phone use in case of power failure.
• Extra Alert jack for external notification device.