IP Office Manuals
IP Office 1408 Telephone Quick Reference Guide
IP Office 1416-1616 Telephone Quick Reference Guide
IP Office 9508 Telephone Quick Reference Guide
IP Office 9608 Telephone Quick Reference Guide
Yealink SIP T42S Quick Start Guide
http://www.candour.com.au/wp-content/uploads/2018/08/Yealink_SIP-T42S_Quick_Start_Guide_V82_20-1.pdf
NEC-SL1100 Quick User Guide