Please open the below link and compare SPA 500S and SPA 500DS model. at the end you will see the both models are design for 3rd Party Call Controllers and Cisco Small Business Pro Unified Communications 320 and 500.http://www.cisco.com/en/US/product...
Please see the below link. This clearly says that 500DS is design for 3rd Party Call Controllers and Cisco Small Business Pro Unified Communications 320 and 500. http://www.cisco.com/en/US/products/ps10499/prod_models_comparison.htmlI have UC320W and...