Hi, Most of our handsets are IP but we have some analogue handsets also with a Cisco SPA122. We are using IP within the office, and ISDN2e out. Some sites say you need to set the outbound proxy, but we are not using a voip provider. The 2 analogue handsets are setup using default settings, and I can call them and 3CX does see them. If I dial the SPA122 menu, I get voice prompts. If I dial 3CX menu, no prompts. If I call 3CX Digital Receptionist, number keys transfer me. In conclusion, everything works but sound Thanks.