John_McNamara_office@es.stratus.com (09/15/89)
Recent postings by Bob Clements and Peter Desnoyers concerning MIT's Dormitory Telephone Service ("Dormphone") bring to mind a number of fond memories. Please forgive the mention of specific names, but it simplifies the telling of the story. In 1914 (?) a young man named Fredrick E. Broderick went to work for MIT, which was at that time still located in Boston. By 1918, MIT had moved to its Cambridge location, and another young man, Carlton E. Tucker, graduated (his thesis was on the effects of air pressure on underground trolley car operation, bespeaking an interest in railroads and transit that lasted all his life). In addition to his interest in railroads, Carlton Tucker was very interested in telephones. During the next thirty years, he rose to full professorship in the MIT Electrical Engineering department, while simultaneously managing MIT's growing telephone systems. I say "systems" because there were two: one rented from New England Telephone, and an MIT-owned system. The MIT system consisted of a small 100-line SXS system that served the EE department (providing dial service long before the NET system went dial in 1941) and two manual switchboards, one in the graduate student residence (150 lines) and one in the East Campus dormitories (550 lines). The MIT system was maintained by Professor Tucker's friend Fred Broderick, who ran an instrument room in the EE department. In 1949, MIT built the first of the West Campus undergraduate dormitories, Baker House. New AECO SXS equipment (300 self-aligning plunger lineswitches, 30 first selectors and 30 connectors) was installed to provide a phone in every one of 250 rooms. In addition, when MIT purchased the nearby Riverbank Court residental hotel a few years later and converted it into Burton House / Connor Hall, 25 lines from Baker were run into that building to provide corridor telephones, each serving about 20 people. Lines from the Baker SXS system appeared at the Graduate House and East Campus manual boards (only about 4 lines each). The Baker System was fairly reliable, except that the lineswitches had a preference chain (of contacts) that often got dirty, resulting a loss of dial tone for up to 100 users. In addition, the dial tone generator was really a buzzer, and occasionally failed. Upon one such occasion, maintenance personnel replaced it with a tape "Dial Dammit, Dial Dammit". The Baker system was maintained by students supervised by Fred Broderick, beginning a tradition / fraternity that would last for 40 years, half of them under Broderick's direction. Sometime in the late 50's a student approached Professor Tucker with the idea of buying some surplus SXS equipment from a South Sea island location and fully automating the dormitory system, which at that time consisted of 100 SXS lines in the EE department, 300 SXS lines in Baker, and about 700 manual lines in Graduate House and East Campus. Professor Tucker explained to the student that the freight costs would be excessive, but the idea stuck in his mind. In about 1960, when Bob Clements and I were both Freshmen, the John Hancock Company equipment (3400 lines of AECO SXS) came on the market. According to one story, MIT dragged their feet about getting the equipment, and the "newest" equipment had been sold before Professor Tucker could convince MIT to pick up the remainder, about 2000 lines. Indeed, three of the 100-line groups that MIT purchased bore date stickers "1922". During the 1961-1962 period, Bob Clements and a couple others (from the original "WTBS" - the MIT station) put the equipment together, and he and I and others installed dial telephones in the rooms. On September 1, 1963, the system went completely dial, with roughly 1500 lines in service. The equipment was located in three separate locations spread over the campus, and included non-aligning and self-aligning plunger lineswitches (see Bob Clement's posting for the difference), linefinders, and lots of selectors and connectors. We had lots of variety. Some of the lines in the Graduate House were party lines with Tip Party / Ring Party selective ringing. Some of the connector switches were Trunk and Level Hunting, and were used for dormitory desks and student activities. Power systems included 70 ampere motor generator sets, large glass cased batteries, and the motor-driven Variac kludge that Peter Desnoyer mentioned. (The latter was given to us by NET. It used a Whetstone bridge circuit that compared the office battery to a reference battery. Current flow in the center of the bridge operated polar relays that flipped field capacitors in a 220V motor that operated the Variac. The Variac in turn regulated Tungar rectifier tubes.) Since this was 5 years before Carterphone, there was no connection to the outside world, and there was no operator. With the advent of Carterphone, various interconnection methods were employed, including one where the MIT operator (at the NET owned switchboard) used one cord set to set up the call and another (via a second jack) when the called party answered. Needless to say, disconnections were common. In 1976, the NET PBX (about 7000 lines of SXS) was replaced with a CO Centrex (1A ESS). Shortly thereafter, direct inward dialling was installed between the CO and Dormphone, permitting anyone in the world to call into 40-50 year old equipment. As Larry Lippman has pointed out, a good ear is an important maintenance tool, and it was easy to tell the difference between the slow and irregular dial pulse strings generated by Dormphone dials, and the crisp and rapid perfectly timed digits incoming from the ESS. Since MIT did not want to have to bill the students, all outgoing calls were credit card / collect / third party, and all incoming calls were greeted with a recorded message "This is MIT, collect and third party calls are not accepted at this number". The recorded message was stored digitally and was the highest tech thing ever to grace Dormphone. It was also the subject of several hacks, as people would break into the exchange and change the recording. During the late 70's and early 80's, additional dormitories were added to the West Campus, and equipment was purchased from American Optical and other sources, to bring the total number of lines in service up to about 2800. Meanwhile, the ancient equipment, including the 300 lines of 1922 equipment, continued to serve well past its 40 year design life, and remained in service until August 1988, when MIT installed a 5ESS purchased from AT&T. All of the Dormphone equipment was scrapped. Fred Broderick's name lives on amongst MIT students as a station at the Tech Model Railroad Club (recipient of a lot of Western Electric college gift equipment via Fred). Carlton Tucker's name also is immortalized in a TMRC station (he was the TMRC faculty advisor), and in a follow-on to his Wire Communications course, 6.311 Telephony. To me, Dormphone lives on as the most fun job I ever had.