I got into telephony in 1990 or so, installing Mitel Smart-1 dialers for a long distance reseller that used about 10 Mitel SX-200 Digitial PBX's as their long distance reseller switches. Eventually moved on to maintaining the switches for a while, then going to school on the 200. Was hired by the local telco to work in their commercial service area on key systems and PBX's, which was then acquired but a larger co-op that was Mitel and Nortel dealer for some time and in the early 2000's moved to Rochester, MN, where I worked for a dealer that serviced south eastern MN, including the Minneapolis Twin Cities area, for several years, then back to a coop, and with a vendor in the Minneapolis area again.
I can't really list everything I have worked on over the years, it would take to long... everything from 1A2 key systems to modern virtualized VoIP systems, going from a time when we carried toolbelts and not laptops (we had one that the entire 12 person department could share), to now when tools are nearly obsolete.
I have been trained and certified in Nortel, Avaya, Comdial, Inter-tel, ESI, Digium, Broadsoft, and Mitel products (I have like 120+ certs with Mitel and 30-40 Nortel certs). On the data side I have my CTP certification, and a bunch of webinar and non-certification training, but most of it was learned on my own or forced "as needed". Not to mention nurse call systems, the company I work for now does custom software integration between Mitel and Asterisk based systems and nurse call systems using SIP application servers and iPhone and Android apps, besides the normal Mitel installs.
Oh, and it runs in the family... My father was with a telephone coop for 35 years before he retired, started as a mechanic moved into the field doing construction, then combination tech, key systems, networking, mobile phones, and eventually retired with a cushy area combination tech job that was mostly a lake resort area.