Please have a look at the relevant links for user manuals and installation guides for different Telephone Adaptors (VoIP):

HandyTone HT488 Telephone Adaptor (Analog)

• User Manual
• Installation Guide

HandyTone HT486 Telephone Adaptor (Analog)

• 486 User Manual
• 486 Installation Guide

HandyTone HT386 Telephone Adaptor (Analog)

• 386 User Manual
• 386 Installation Guide

HandyTone HT286 Telephone Adaptor (Analog)

• 286 User Manual
• 286 Installation Guide