BT Navigator / EKLU - UK Vintage Radio Repair and Restoration Discussion Forum

terrystokoe · 9th Aug 2023, 2:19 pm

The BT Navigator (aka “EKLU”) was an electronic replacement for the mechanical key and lamp unit in service in the early 80's.

In 1985 I left college and began working for GEC Telecoms in Newton Aycliffe. After a year or so I was involved in designing and prototyping the electronics for the central control unit for the upcoming EKLU system.

It was based around the NEC V20 microprocessor which was an 8088 compatible device. I believe it was also the first time GEC had used semiconductor switching for the audio channels rather than mechanical relays.

I left GEC during the EKLU pre-production runs to move to BT, so never saw the finished article until a colleague gave me the attached glossy with the shiny new Navigator name. Don't know how popular they were (if at all) or how reliable they turned out to be.

Maybe not quite vintage, but getting there.

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Roger Ramjet · 9th Aug 2023, 6:47 pm

Nice looking unit Terry,

Was it stand alone just with line & extension ports + power supply or did it need a separate interface.

Rog

terrystokoe · 9th Aug 2023, 9:07 pm

Honestly can’t recall exactly how things were set up Rog, but from what I do remember, the central unit will have linked directly with the exchange lines and the handset terminals. I recall a lot of effort going into the telephony audio side trying to meet the (at the time) very strict BT specifications.
I only wish I’d seen the final product in the flesh so to speak.

9th Aug 2023, 2:19 pm	#1
terrystokoe Triode Join Date: Aug 2023 Location: Gateshead, Tyne and Wear, UK Posts: 11	BT Navigator / EKLU The BT Navigator (aka “EKLU”) was an electronic replacement for the mechanical key and lamp unit in service in the early 80's. In 1985 I left college and began working for GEC Telecoms in Newton Aycliffe. After a year or so I was involved in designing and prototyping the electronics for the central control unit for the upcoming EKLU system. It was based around the NEC V20 microprocessor which was an 8088 compatible device. I believe it was also the first time GEC had used semiconductor switching for the audio channels rather than mechanical relays. I left GEC during the EKLU pre-production runs to move to BT, so never saw the finished article until a colleague gave me the attached glossy with the shiny new Navigator name. Don't know how popular they were (if at all) or how reliable they turned out to be. Maybe not quite vintage, but getting there.

9th Aug 2023, 6:47 pm	#2
Roger Ramjet Heptode Join Date: Feb 2022 Location: Leicestershire, UK. Posts: 690	Re: BT Navigator / EKLU Nice looking unit Terry, Was it stand alone just with line & extension ports + power supply or did it need a separate interface. Rog

9th Aug 2023, 9:07 pm	#3
terrystokoe Triode Join Date: Aug 2023 Location: Gateshead, Tyne and Wear, UK Posts: 11	Re: BT Navigator / EKLU Honestly can’t recall exactly how things were set up Rog, but from what I do remember, the central unit will have linked directly with the exchange lines and the handset terminals. I recall a lot of effort going into the telephony audio side trying to meet the (at the time) very strict BT specifications. I only wish I’d seen the final product in the flesh so to speak.