atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems 1A2 and some old WECO stuff

Hi,

An unusual addition to my collection. This is a full 1A2 compatible speakerphone set / conferencing PhoneBeam unit from Platronics. I don't know if anyone else released an 1A2 compatible equipment, because by the tyme of Bell System break up the 1A2 was already at the end of it's "commercial life" (not talking about useful life, since it can last forever, but it is mostly what was heavily promoted and pushed to the market by the telephone companies at that time).



The unit looks neat and combines in the base unit a set of control buttons and LEDs, base unit microphone, volume control, loudspeaker, infrared receiver for remote transmitter and a charging bay for it. So basically the base unit can be used alone with only operating the microphone it has on the front panel. This makes it pretty much comparable with WE 4a Speakerphone with 2 control options - "On/Off" and "Mute", but muting button is electronically locked, so once you press it once momentarily the mute (and corresponding mute LED) will be activated permanently till you press it again to return into the conversation mode. So no need anymore for the quarter buck coin on those long boring teleconferences.



I managed to get the base unit new in the box. Label states it is made in Japan and I assume one of the stickers is a manufacture date code - week 49 of 1988.



The unit itself appears to be developed around 1983 as all the user manuals and installation guides have this date printd on them. So basically released just before divestiture. The unit was released with several connection options for different types of telephone sets, but of course the most interesting one for me was a 1A2 multi-line compatible. This means the base unit has a normal 50-pin Amphenol connector on the end of the cable, which plugs into any standard 82B connection block directly replacing the plugs of 680A transmitter, 108A loudspeaker and the famous "option plug". According to the installation manual, you only need to disconnect the old power supply to the 4A speakerphone first, since the unit has its own 16V DC power supply to connect to the mains. Well, it is designed like that and it works like that. I believe there is also an option to connect additional wires inside the base unit to use couple of relays inside for controlling the lamps or ringer cutoff, so basically the same as 4A'a option plug functionality.



Sorry for the mess of cables. This still serves as a permanent "temporary" setup.

I don't think they have sold a lot of this units, since originally I have lost the hope to find this neat tiny IR transmitter unit to my NOS base piece. However later the spirit of eBay was very kind to me and showed up and auction for 5 PhoneBeam base units, all dirty and old with cut cables and 2 of those had a transmitting unit on them. So what could one do - just buy all of them since I'm not sure the seller had any hope for anyone else to be interested in this stuff. As transmitter has a battery pack inside, being 30 years old I never expected that to be in good condition since all these batteries start leaking at some point creating a mess on all metal parts and PCBs. For those who saw any of WE 2872A2M Touch-A-Matics with the backup battery for memory unit on the bottom of the set - you know what I mean. So my best guess was, if one out of the two transmitter unit works or appears to be reparable - I'm already lucky. But actually this time I was more than lucky: first of all the box came with 5 bases and 3 transmitters, not 2. Of course they all were damaged around the batteries as expected with salt and oxidation all over the place. But I removed the batteries packs and checked those with a normal 7V power supply and guess what - all three were operational without any repair, coupling, restoring. Either this is about all old electronics which was just built to last, or specifically because Japanese know something special about how to make electronics. Anyway, next I disassembled the battery packs (interestingly enough white paint print on batteries says they were assembled in Mexico and the cells themselves stamped to be made in Singapore, not in Japan - probably this is why they failed after just 30 years). This is how internal cells look like:



This shape of NiCd cells is extremely difficult to find (though I recently have found a pack of similar cells in the UK - will try them out later). So for the first experimental unit I used two cells of Li-polymer subminiature batteries of 3.7V - so in total 7.4V nominal - very close to original 7.2V of six cells by 1.2V. Those 2 fit perfectly into the pack shell leaving plenty of free space and they are much lighter (actually I will probably need to add a metal dummy weight to it since the new unit is so light in weight that it probably may have issues with pressing itself down properly in the charging bay. But anyway - the final design is still under construction. In comparison with old 90 mAh pack my LiPo setup delivers unprecedented 240 mAh of charge which apparently should move the limit of single continious use of receiver (in conversation mode) from stated by manufacturer 3 hours to something which I believe exceeds the 8 hours working day.



This unit is interesting since it uses an unusual technology for establishing a voice link between the transmitter and the base unit (no, it is not Bluetooth - forget about this in 1983). It uses an infrared carrier to transmit voice from the remote unit to the receiver of the base station. So anywhere whithin the same room an invisible IR light (similar to the one used for regular remote controls for TV sets, etc.) will deliver the voice over the optical link. The transmitter has a microphone and about 5 or 6 LEDs under the red cover on the top edge. I think this was a strategic choice made by Plantronics, since would they use any radio frequency carrier for this set (which appears to be an easy choice), they would have to apply for a license/approval from FCC back in 1983 which I believe could add some $$$ and time lost on the introduction of the new unit. As the transmitter inside has only a relatively small and primitive PCB I do not think this system use any kind of digital conversion. I assume it is an analog transmison, probably utilizing some sort of FM for the voice over IR light.



The transitter has only one 2 position switch which allows to activate and deactivate the speakerphone. So if you have the proper line preselected on your 1A2 connected phone - you can answer it remotely from the transmitter anywehere in your room/office. As well as disconnect the call when finished. This unit was marketed as the first "echoless" conferencing unit, since apparenly by placing the microphone directly in front of the person to talk you eliminate all sorts of echo. It also has a metal clips to put it into you shirt pocet and fix it there for conversation. Thus a microphone and transmitting LEDs look out of your pocket and all the rest is hidden inside.



Anyway, this thing appears to be a one of a kind example of using alternative technology to deliver telephone advanced functionality, is a nice technological artifact and besides all of this - works perfectly in my 1A2 setup. Of course it is not so fundamentally built and recognizable like WE 4A speakerphone with all of the plastic color choices (which appear to go crazy in price on eBay nowadays), but it nice and it works.