Telecommunications (Telecom) Electronics
My experience with telecommunications equipment goes all the way back to the late 1970s when I worked for GTE Lenkurt
(now Siemens). At that time, as a product support engineer, I dealt on a day to day basis with the manufacturing of
central office equipment. Later, in the late '80s when I worked for General Instrument's VideoCipher satellite TV
division, I wrote descrambler firmware to communicate with a telephone modem "sidecar". The purpose of the sidecar
was to report impulse pay-per-view programs ordered by a subscriber.
I continued to be involved in telecommunications into the new millenium. For example, I designed a telephone line
pair tester for Gale Electronics:
I also wrote assembly language MicroChip (PIC) firmware for an emergency alert system.
The system is used primarily by the elderly. The Personal Alert unit (PAL) is responsive to an RF pendent worn
about the neck. If the elderly person should need assistance, he or she presses the button on the pendant,
and the personal alert system places a phone call to a central monitoring station. Monitoring personel can
then talk to the person using the speakerphone and dispatch EMS if there is no response or the person seems to be
Other work I have done has exposed me to Asymmetrical Digital Subscriber Line (ADSL) modem technology.
ADSL incorporates a process for determining the frequency response of the phone line between a central office
node and the customer's premisis. Using this information, the ADSL modem assigns bits to "bins". These bins form
the basis for transmitting data using discrete multitone transmission (DMT). By detecting what the phone line is
capable of carrying at each DMT frequency the transmission of digital information to and from the CO node can be optimized.