I had the same problem recently when I looked online for this manual and a similar model’s manual and thankfully I was able to solve the mystery and locate it. Even though the answering machine says it is a Philips AD2735, the correct user manual for it is the manual for the AT&T 1725. Once I figured this out, it was super easy to locate the manual on AT&T’s website... and sure enough, these two products are identical!!!

I figured this out when I ran across an old article discussing a joint venture between Lucent Technologies (AT&T) and Philips Electronics. Apparently the two companies decided to merge together and combine their resources to develop technologically advanced answering machines. After the products were developed, each company marketed them under their name with a different model number, but both were selling the same thing! The reason we couldn’t find the user manual for the Philips model is because Lucent (AT&T) has the manuals!

In case this might help someone, I own two of these answering machines and can vouch that the user manual for the Lucent AS40 is the same as the AT&T 1715 and the Philips AD2735 is the same as the AT&T 1725. Here are the models that were produced during the joint venture:

AT&T/ Lucent 1715 = Lucent/ AT&T AS40
AT&T/ Lucent 1725 = Philips AD2735
AT&T/ Lucent 1717 = ?
AT&T/ Lucent 1815 = ?
AT&T/ Lucent 1825 = ?
AT&T/ Lucent 7625 = ?
AT&T/ Lucent 7630 = ?