On the 28th of May, sk113573: How to configure VoIP on Locally Managed 600 / 700 / 910 / 1100 / 1200R / 1400 appliances has been updated again ! First seen on October 5th, 2016, this is the most important source for a working configuration of VoIP on SMB Appliances.
While e.g. the Check Point 1400 Appliances Locally Managed Administration Guide R77.20.87 only has page 25 dedicated to basic VoIP configuration, sk113573 is presenting 5 different VoIP topologies and basic configuration rules to make VoIP work - so many have found this sk very valuable. Additional information can be found in ATRG: Gaia Embedded Appliances. The other five SKs available only feature specific issues / errors with VoIP on SMB.
CCSP - CCSE / CCTE / CTPS / CCME / CCSM Elite / SMB Specialist