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AT&T phone system considered

and Simson L. Garfinkel

The MIT Telecommunications Office has recommended purchase of a new telephone switching system to replace the Centrex and Dormline networks, according to Director of Telecommunications Morton Berlan.

Acquisition of the computerized control switch, a #5 Electronic Switching System (5ESS) from American Telephone & Telegraph (AT&T) Co. Information Systems, must be approved by the MIT administration. The 5ESS would provide improved service, including data transmission capability, at a lower cost to the Institute than the current system, Berlan said. The new system would be installed in the summer of 1987 at the earliest.

The decision to buy the new switch was prompted by concern about the "constant escalation of [Centrex] prices," desire for a state-of-the-art system, and concern about the deterioration of Dormline, according to Berlan. It is becoming increasingly difficult to maintain Dormline, he explained, because its electro-mechanical switches are obsolete and are no longer supported by the industry.

Berlan hopes that the new MIT system will provide service equivalent to an "outside line" rented from New England Telephone. Although the Institute will continue to permit students to rent outside phones, MIT Telecommunications will try to offer students local Boston area calling and connection to one of several long distance carriers in addition to local campus dialing.

The same equipment will be used to switch both dormitory telephones and Institute office telephones if the 5ESS switching system is installed. "Under this scheme there is not going to be a dormline per se," Berlan said.


Committee Chose New System


An ad hoc advisory committee, including members from the academic, research, and administrative areas, evaluated eight proposals submitted by companies and decided that the 5ESS was "the best for MIT," Berlan said.

The Academic Council and the Executive Committee of the MIT Corporation must approve the proposed purchase before an order can be placed. If the order is not placed by October 1, the new system will not be received until after the summer of 1987. "I'm trying to get all these issues resolved, hopefully by the end of this calendar year," Berlan said.

Because extensive construction is necessary, the new switching system cannot be installed during the term. If the conversion is delayed beyond the summer of 1987, it must wait until January 1988 or the following summer.


Improved Features Offered


The new system will allow special features, such as call waiting, as well as standard telephone service. Features must be paid for on a monthly basis under the Centrex system. Berlan hopes to offer features free of charge with the 5ESS.

The 5ESS will permit digital data communication at speeds up to 56 kilobaud. Customers desiring high-speed data communication would have to purchase a higher-priced telephone equipped with a 25-pin computer connector and pay for the additional data-switch service.

A single telephone line would be able to carry digital and voice communication simultaneously, eliminating the need for dual lines. The cost of telephone service will therefore decrease for many offices, because fewer lines will be needed, Berlan explained.

With the present MIT telephone system, a modem is necessary for data communication. Most modems are limited to a speed of 1.2 kilobaud, and require the rental of a dedicated phone line.


Dispute with Company


The 5ESS would connect to New England Telephone's network through "trunk" lines. Trunk lines can be designated for either residential or business use. Berlan has asked New England Telephone to allow MIT to buy a number of residential trunk lines for the exclusive use of students. Under this arrangement students would pay a flat rate and other users would be charged for message units.

New England Telephone has not agreed to Berlan's proposal. "The mixing of residential and business lines in the same PBX [Private Branch Exchange] system is inconsistent with existing Massachusetts tariffs," stated New England Telephone Manager of Public Relations Bill Welch. "Therefore we simply cannot provide that service."

According to Berlan, New England Telephone is reticent because acceptance of the proposal would set a precedent for the company's relations with other universities. Many area universities, including Harvard, are considering replacement of their current telephone systems with university-owned switches. If student lines are classified as "residential," Berlan said, New England Telephone stands to lose revenue.

Berlan intends to bring the issue of classification of student "trunks" before the Department of Public Utilities within the next two months.

New England Telephone policy would also prevent MIT from connecting its switch to long distance carriers through existing New England Telephone trunks, Berlan explained. Welch said, "Customers have the option to connect to long distance companies through our network or directly."

According to Berlan, however, New England Telephone would not automatically transmit to the long distance carrier the 7 digit billing code. Without the telephone number, the long distance carrier cannot bill the originator of the call.

Berlan is considering directly connecting the 5ESS to long distance carriers. He is discussing this possiblity with AT&T Communications, Microwave Communications Incorporated, and General Telephone and Electronics Sprint.


Much Construction Needed


Several factors prevent the installation of the 5ESS before the summer of 1987. The software package which Berlan wishes to run on the switch, called 5E4, will not be available until early 1987. In addition, MIT must allocate and prepare physical space on campus for the switch. The 5ESS will require about 3500 square feet.

Rewiring of the entire Institute would be necessary for installation of any on-campus telephone switch. Parts of the underground phone duct system are clogged and must be cleared. Some buildings, such as N51 and N52, have no telephone ducts connecting them with the rest of the Institute, so new ducts would have to be built.

The Telecommunications Office intends to "create a parallel system, to build a new system while the old one is still functioning" to prevent an interruption in telephone service, Berlan said.

The 5ESS, if approved, will have a capacity of 14,000 telephone lines when installed and is expandable to a maximum of 100,000 extensions. MIT now has over 10,700 Centrex telephone extensions in the 253 and 258 exchanges and 2800 Dormline extensions in the 225 exchange.

Berlan estimated the total cost of conversion to the new system, including the price of the switch, renovation and rewiring, and replacement of every telephone instrument on campus, at $19.3 million. The cost may be slightly lower, he noted, because not all offices will need to replace previously purchased telephones.