After a few web searches, I have found the following URLs which may be helpful:

Potential CRM VOIP Addon
http://crmaddon-factory.com/using-act-with-ringcentral/

Potential VOIP Plugin to use with ACT!
https://voipstudio.com/click-to-call-with-sage-act!-pro-and-voipstudio-sip-tapi/

Q/A about VOIP integration w/ ACT!
https://community.act.com/t5/Act/Noobie-question/m-p/310048/highlight/true#M75845

How to setup the ACT! Dialer
http://kb.act.com/app/answers/detail/a_id/13810

Additionally, we received a post in the RingCentral Community from a customer who wanted to setup SIPTAPI to use with RingCentral and ACT! You might reply to this developer and ask how their progress is coming in this thread: https://devcommunity.ringcentral.com/ringcentraldev/topics/how-to-integrate-ringcentral-with-siptapi...

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