Hi Team, We've just rolled out a 3CX v15 for Linux install for a client (16 license, professional), with Patton SN4114/JO trunked to 4x PSTN lines. They are not using VoIP, however they have Yealink T42G, Yealink T46G and Yealink T48G handsets. The customer has advised that their previous NEC 'digital' phone system was better than the new system we've put in. Apparently they feel the clarity of calls was better. They are hearing crackling on the call. Originally we had to bump up the output gain on the Patton to around 7 db, otherwise their customers could not hear them. Can anyone suggest things we can do to improve call quality? It's rather disheartening to hear a customer who you've just sold 30x handsets tell you they don't think it's as good as the piece of junk you pulled out.