# Panasonic KX-TD816 PABX/PBX

I've bought this small PBX for my office. While not exactly _needed_, it can still be useful for a thing or two. This page compiles knowledge and information on this unit that I've been collecting around. 

## Alert: Rant incoming

As a strictly proprietary project, generally sold by Panasonic representatives, any very technical insights are pretty hard to come by. For some reason, folks that worked with this unit tend to withhold anything they have. People will either try to sell you this data or boast they have it in Sundance Communications. At best, you'll find a thread that ends in «sent you via PM.» I, however, don't think even Panasonic would bother with anyone sharing schematics and software on a unit so old that the configuration software is written for MS-DOS. So, for the sake of open knowledge, I'll share what I find here, albeit it's not much. As I grow frustrated, I also got salty. Sorry, I can't avoid it. This article may be a little too rich on salt. 

## My unit

My PBX is particularly of the KX-TD816BX model. It sports a KX-TD170 expansion for eight more extensions. Since I have no use for it, it's disconnected. 

It's also **impossible** to find it's service manual. You'll either find it in some lists on rather obscure sites trying to sell it or at `diagram.com.ua`, where you'll also find it on such lists, but it will also give you the false hope that it will exist somewhere in their «««free library»»». It doesn't not, please give up before losing sanity. 

There's a service manual for the UK offering, KX-TD816E. But it's quite different from mine, while it shares some design premises. That one has a big, single motherboard, connect to the extensions card. RTC, RTC battery, ROM and RAM chips are also on a separate board, firmly connected to that motherboard.

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