For a long time, Western Electric held a sizable interest in Northern Electric, which supplied Bell Canada, as well as some of the Canadian independents. In 1956, however, a landmark court decision, the 1956 Consent Decree/Final Judgment of the 1949 antitrust suit brought by the U.S. Department of Justice forced AT&T to divest itself of its Canadian holdings, including Northern Electric. As a result, Northern Electric gradually began producing more and more original designs of their own, although they continued producing the basic 2500 for quite some time.
Northern Electric changed their name to Northern Telecom in 1976, after trying to expand internationally, and finding that there was already a company named Northern Electric in existance in the United States making electric blankets.
In addition to the standard "DigiTone" 2500, Northern Telecom also made a "DigiPulse" version, which looked and felt just like a DTMF-based 2500, except that instead of emitting dual tones, it emitted timed pulses like a rotary dial. Although this model did feature the * and # keys, these keys did nothing when pressed, since there was no rotary equivalent for those keys.
The thinking behind the DigiPulse sets was that they could offer much of the convenience of push-button dialing without requiring a massive investment in upgrading old Step by Step based central offices that served many smaller towns and rural areas. The advent of small, affordable digital switching systems like the DMS-10 in 1978 considerably reduced the market for DigiPulse sets, however, so not very many DigiPulse sets remain out there today.
In the mid 1980's or so (HELP ME BE MORE SPECIFIC), after several field trials, Northern Telecom started producing the QSQE-2500 series. Although these models still featured the traditional C-type ringer and body design, the QSQE series featured a new electret transmitter in place of the traditional T1 carbon granule transmitter, and a large-scale integrated network circuit/DTMF keypad, replacing the conventional induction coil-based network circuit and the tuned coil/transistor-based keypads used in the old QSQM-2500 series. Not many of these survive today.
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