Usually we use a 10 digit number system, computers may use binary 2 digits, hexadecimal 16 digits or octal system with only 8 digits.
So we choose to go for this is an early digital telephone
To be serous, I have an Ericsson with 5 buttons, an Antwerp telephone with 10 lines, and Norwegian telephones with 10 and 30 lines. So yes, this is probably an intercom. No reason for not being able to use it as a an answering telephone. (If you want)
Are you able to take pictures of the inside, and if it is a diagram there
dsk
