What is a 8-28?
Are you refering to a KX-TD1232 with 1 8 port expansion card?
1st thing is to connect a SLT to the fax Ext.
Set up the TVS 95 for auto fax recognition and assign the correct Ext.
Set whichever line is used for fax to DIL 1-1 to voicemail, (Ext i65) Have someone send you a fax and make sure the TVS directs the call to that Ext. (answer the slt) This way you know that the system and the TVS is working properly.
Then set the fax portion to 1 ring and silent and connect it and test again.
i would set that fax line to be the last line to call out on, either put them all in the same trunk group or reverse your trunk group order, either way.
This fax line should be the last line to receive voice calls on, ( lines 1 & 2 should be busy) this way the A/A will answer and play the greeting.