This is a long shot, but can anyone suggest where I can get hold of instructions for an (old) Aria 28 PABX phone system.  Purchased about 30 years ago (from Telecom I believe) but still going strong and I want to change the ring options etc.  Have looked at newer models on line but they don't seem to relate to the Aria 28 system.  Have trolled the internet without any success.  Any help appreciated.