Hello ManUtd77,
welcome to the Polycom Community.
WIthout knowing anything about your infrastructure this is difficult to answer.
The SSIP6000 is a SIP phone and could make an outgoing call into the RMX via ISDN.
You could also setup a trunk or a User via SIP on the RMX to receive a SIP call from the SSIP.
If you have a DMA you could register the SSIP6000 to it and make calls into the RMX.
As you can see by above there are plenty of possibility's and I would advise you to work with your Polycom reseller.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Best Regards
Steffen Baier
Polycom Global Services
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The title Polycom Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. My official "day" Job is 3rd Level support at Poly but I am unable to provide official support via the community.
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Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels.
Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's
