@Mark Ollig
Over the past 50-plus years, telecommunications has undergone remarkable change.
Over the past 50-plus years, telecommunications has undergone remarkable change.
Before electronic telephone central-office switching systems were introduced, many local telephone exchanges used electromechanical relay switches that were strictly analog and loud.
The GTE-Leich (pronounced “like”) electromechanical switch I worked with provided dial tone and routed local and long-distance calls through its line finders, selector links, hundreds group connectors, and associated relay circuits.
Those components were mounted on jack-in relay bars, which were plugged into wired backplanes, connecting each unit to the main office cable wiring.
Small 30-volt Sylvania wire-lead lamps on various links served as visual indicators.
I can still see those lamps glowing and hear the relays clicking on vertical bars inside the metal-framed cabinets in the dial room.
Aside from growing up in the telephone business, my formal technical foundation began in the late 1970s with a telecommunications degree from Wadena Technical College.
When I went to work for the local telephone company, I spent much of my time in the field splicing cables, climbing poles, installing aerial cable using a process we called lashing, and running aerial and buried telephone drops to homes and businesses.
When the phone company still leased its phones, the job included installing, repairing, and maintaining telephones and related equipment, such as extension phones and ringers.
There were also payphones to maintain, along with lines to troubleshoot when customers experienced noise, a hum, or no dial tone.
The work changed from day to day, which kept things interesting.
Over the years, my role ranged from wiring and soldering to programming, calling translations, and routes, along with hardware maintenance and software upgrades.
Before cellphones, cable TV, phone service, or Voice over Internet Protocol (VoIP), people depended on their hard-wired telephone as their main lifeline.
After summer storms, we were outside repairing lines that had been knocked down by wind or damaged by falling branches and lightning strikes.
On blowing-snow, subzero winter days and nights, troubleshooting could mean climbing an icy telephone pole or digging out a snow-buried pedestal so a business, a house in town, or a country farmhouse could make and receive calls again.
By the mid-1980s, my work also involved digital switching platforms and programming call-routing translations on a keyboard and video display unit (VDU).
By 1998, while working at TDS Telecom, I was installing and maintaining T1/DS1 and Primary Rate Interface (PRI) circuits used to transport voice and data, while working with Signaling System 7 (SS7) trunk-circuit signaling for call setup and routing.
Starting the same year, the telephone company began installing Digital Subscriber Line, or DSL, internet service over existing copper telephone pairs.
Asymmetric Digital Subscriber Line, or ADSL, provided homes with faster downloads than dial-up, while High-bit-rate Digital Subscriber Line, or HDSL, provided businesses with dedicated T1-class voice and data circuits.
On-premises private branch exchange (PBX) systems have largely given way to hosted IP PBX (HPBX) and other cloud calling platforms, which provide business phone features without requiring customers to maintain their own switching hardware.
VoIP brought me into programming softswitches, short for software switches, that handled customers’ local and long-distance calling over IP-based networks.
The Metaswitch platform I worked on is a softswitch, a software-based, programmable telephone switch that carries voice calls over internet-based networks using VoIP.
Operating a softswitch also involves programming routers, managing servers, and maintaining the software that keeps the whole system working.
Before I retired, I helped decommission many legacy digital switches as softswitches were replaced by newer telephone switching equipment.
As telecommunications networks expanded beyond copper, the transport infrastructure moved from T1 digital carriers and DS3 lines running at 44.736 megabits per second to gigabit fiber-optic systems.
These fiber systems used Synchronous Optical Network, or SONET, technology to carry voice, data, and video at speeds up to 40 gigabits per second.
Later networks adopted Optical Transport Network standards to handle data-heavy traffic at 100 gigabits per second and beyond, now reaching 400 and 800 gigabits per second, and even 1.6 terabits per second.
In typical fiber-optic internet service, an Optical Line Terminal, or OLT, at the provider sends data as light pulses through glass fiber.
At the home or business, an Optical Network Terminal, or ONT, converts those light pulses for the customer’s router or Wi-Fi equipment and serves as the handoff point between the provider and customer.
Data moving across the world’s networks is now measured in exabytes each month, with one exabyte equal to 1 billion gigabytes.
These networks carry email, web pages, social media, voice calls, video streams, banking, commerce, cloud applications, business data, artificial intelligence (AI) workloads, and data-center traffic.
Despite all the technological advances, the true value of telecommunications still lies in reliability and customer confidence that the network will work when needed.
