I want to replace a SPA-3102 being used as a PSTN gateway. Which GrandStream should I try? The GWX-40X4 or the 410X? I have a SIP trunk configured and also have a PSTN line that I want to have access to via the 3CX PBX. The SPA-3102 works for this but I have an issue of 4 tones that happen during the PSTN call at random times. I want to try another Gateway. Thanks for your thoughts and recommendations.