I do not have any information on your specific phone but I'd like to try and help. Typically a multi-line phone set up like this would need a way to intercom between phones. I have not seen one that can utilize the same wires as the phone service but I also have not looked. It would also need each phone to have it's own identification (extension assignment). You only need two wires for each phone line but for intercom there most likely needs to be another pair of wires connecting all the phones together. I hope you have a manual. Look carefully at the section dealing with wiring up the phones to the phone lines. It should mention intercom at some point and what is required. Also, you can have up to 16 phones. Each phone must have a setting to choose a number between 1-16 or maybe 10-25, 100-115. By default these will all be at the same setting and you would not be able to intercom.
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