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-   -   Ambassador/Senator external extension adaptor (https://www.vintage-radio.net/forum/showthread.php?t=145523)

Dave Moll 9th Apr 2018 10:59 am

Ambassador/Senator external extension adaptor
 
I have acquired one of the above adaptors, which I have now connected up to an Ambassador CCU is described on Bob Freshwater's site.

Nearly everything is working as described:
dialling 81 (loop dis.) etc from the external extension gives access to an external line
an incoming call rings the external extension as long as "remote answering" on the adaptor is selected (button illuminated)
I can call the external extension from an Ambassador terminal connected to another extension

... but I cannot identify how to call the other extension from the external one. The above-mentioned site doesn't include this function under "External Extension Facilities", but merely says that "The facilities of an external extension are similar to those [of a normal extension]" with the exception of those described. As inter-extension calls on an Ambassador system are initiated by pressing keys on the extension stations (which are not present on an external extension), this function is clearly not similar.

Is this function only available on a Senator (where inter-extension calls are initiated by dialling the extension number)?

OscarFoxtrot 9th Apr 2018 11:41 am

Re: Ambassador/Senator external extension adaptor
 
Sir may wish to peruse the user guide linked therefrom

http://www.britishtelephones.com/useguide/ambassa1.htm

40 Bell Off.
41 Bell On.

Dial 9 to use the first available free line or:
81 First Line.
82 Second Line.

Intercom: Dial 0 followed by the terminal number.

External extension adapters are not compatible with MF signalling, if MF is required a dual signalling telephone is required and must be set to LD, and only switched to MF once exchange dial tone is received.

Dave Moll 9th Apr 2018 2:00 pm

Re: Ambassador/Senator external extension adaptor
 
Whoops. I forgot about the user guide. However, I had already tried "0" followed by the extension number without success. When I dial the "0", the light for the external adaptor's extension lights on the other terminal, but nothing happens when I follow this with the extension number. And yes, I had established that LD dialling is required.

edit: I haven't yet tried hooking it up to a Senator, but I assume the "0" is omitted there unless dialling extension 10 (whose code is "0").

Dave Moll 9th Apr 2018 3:04 pm

Re: Ambassador/Senator external extension adaptor
 
Having now tried it on a Senator, it works by dialling with the "0" first, so that would explain the non-functioning on the Ambassador, as the extension number after the "0" is simply being passed to the CCU rather than being translated into an extension line select command as required by the Ambassador.

Incidentally, I only get dial tone on the external extension after dialling the "0".

OscarFoxtrot 9th Apr 2018 8:47 pm

Re: Ambassador/Senator external extension adaptor
 
software version incompatibility with the Ambassador?

Dave Moll 9th Apr 2018 9:28 pm

Re: Ambassador/Senator external extension adaptor
 
So, would there have been some sort of reprogramming process to change between Ambassador and Senator working? Clearly, different behaviour is needed depending on to which system the unit is connected.

Euros1951 9th Apr 2018 9:45 pm

Re: Ambassador/Senator external extension adaptor
 
Didn't the Ambassador have individual buttons for selecting which extension you wanted? Therefore you cannot dial extension numbers on that system. it should be fine for the Senator.

OscarFoxtrot 9th Apr 2018 10:11 pm

Re: Ambassador/Senator external extension adaptor
 
Double check you're calling the right extension number and it's not diverting to another/non-existent station? :-) Otherwise I'm a bit stuck.

Dave Moll 10th Apr 2018 6:34 am

Re: Ambassador/Senator external extension adaptor
 
Actually, I woke up this morning to a bit of a light-bulb moment along the lines mentioned by Euros1951. Indeed, the Ambassador/Senator terminal has five buttons:
On a Senator, these five buttons each select an external line.
On an Ambassador 2+4, the first two select outside lines and the remaining three select intercom signalling to the other three extensions.

So, the thought went... what happens on an Ambassador if I type "83", "84" or "85"? I therefore tried it out with the one I have lashed up at present with a terminal on extension 1 and the external adaptor on extension 2 - and bingo! "85" from the external extension dials extension 1. I'll wire up another couple of terminals to extensions 3 and 4 later and confirm that these are signalled by "83" and "84" respectively.

Edit: actually, I should have said that the terminal has five selection buttons. It has more than five in total, but the other two are for "divert" and "hold". Who said I'm pedantic? ;)

Dave Moll 10th Apr 2018 10:18 am

Re: Ambassador/Senator external extension adaptor
 
Yes, now confirmed. "81" through "85" from the external extension perform exactly the same as those five buttons on a terminal, performing the same functions of selecting external lines or internal extensions - with the same situation that which button/number selects which extension varies according to the initiating extension.

Problem solved.

Dave Moll 10th Apr 2018 10:26 am

Re: Ambassador/Senator external extension adaptor
 
Somewhat off-topic, but still on the subject of Ambassador/Senator, I notice that whereas the Senator has three connections for each external line (marked "A", "B" and "E" for the line legs and signal earth) plus a fourth one unmarked and presumably unused, the Ambassador has four (marked "A", "B", "C" and "E"). Does anyone know the function of "C", if any?

OscarFoxtrot 10th Apr 2018 12:17 pm

Re: Ambassador/Senator external extension adaptor
 
Probably third wire supervisory signalling where the Ambassador is piggybacked onto a cordless PMBX.

"Ambassador ESS systems can provide earth-loop recall or 'C wire supervisory' signals to host system."

http://www.britishtelephones.com/pmbx2_3.htm

There were still plenty of those PMBXs in use until they were withdrawn in 1994 where the size of the installation did not justify the newer eg Herald systems, and many of them had a Plan 105 (later, Ambassador) piggybacked on for boss-secretary working.

Dave Moll 10th Apr 2018 4:21 pm

Re: Ambassador/Senator external extension adaptor
 
Thanks for clarifying that little detour.

Dave Moll 14th Apr 2018 3:05 pm

Re: Ambassador/Senator external extension adaptor
 
Returning to the question of internal calls from the external extension, some further digging has come up with an Ambassador ESS system manual in which my conundrum is solved. Buried in the text on page 3.16 is a paragraph reading as follows: Mounted on the circuit board contained within the Adaptor is a "link" type switch SW2. This switch must be OPEN..

I had noticed this switch and wondered whether it served this sort of purpose, but didn't wish to alter it without the appropriate confirmation of its function. Presumably, the equivalent text in the Senator system manual (which I haven't managed to track down) says that this switch must be CLOSED - as the one on my unit is. Before I next fire up my demo setup, I shall open this switch, which should make the external extension work on the Ambassador as described, rather than using the kludge I described earlier.

And by the way, the manual also confirms OF's supposition about "C wire" signalling.

Dave Moll 14th Apr 2018 8:32 pm

Re: Ambassador/Senator external extension adaptor
 
Yes indeed, with SW2 open the unit is now changed from "Senator mode" to "Ambassador mode" and "01" through "03", rather than "83" through "85" (which are now disabled), do signal the other extensions.

I note that the manual suggests the external extension should be connected as extension four (which I had done anyway). Presumably this is just to ensure that the extension numbers dialled equate to the correct physical extensions - which they wouldn't otherwise, given that each extension has the three extension buttons assigned starting with button one equating to the next extension in sequence (e.g. on extension three they are respectively four, one and two).

OscarFoxtrot 14th Apr 2018 9:22 pm

Re: Ambassador/Senator external extension adaptor
 
Well done.

Dave Moll 16th Apr 2018 10:50 am

Re: Ambassador/Senator external extension adaptor
 
3 Attachment(s)
Just for interest, here are a few pictures of my completed demo setup...

Dave Moll 13th Jun 2018 9:54 pm

Re: Ambassador/Senator external extension adaptor
 
Quote:

Originally Posted by Dave Moll (Post 1035181)
Buried in the text on page 3.16 is a paragraph reading as follows: Mounted on the circuit board contained within the Adaptor is a "link" type switch SW2. This switch must be OPEN..

I had noticed this switch and wondered whether it served this sort of purpose, but didn't wish to alter it without the appropriate confirmation of its function. Presumably, the equivalent text in the Senator system manual (which I haven't managed to track down) says that this switch must be CLOSED - as the one on my unit is.

Having now acquired a copy of the Senator System Manual, I can confirm that page 10.10 of said manual contains a paragraph including the following:

A 'safety pin' type link, SW2, is* fitted on the PCB of the Adaptor... This switch must be closed.

*The text actually says "if" rather than "is", but this is surely a typographical error.


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