I have all Grandstream phones mostly GXP2000 but a couple of GXV3140s. Problem is the GXV3140 can recieve paging/intercom calls but can't make them. *91 is call feature for cancelling busy call forward on this phone. All my extensions are 100-199 so as soon as user keys *91 call feature kicks in. Works fine on the GXP2000 just problem on GXV3140. Does anyone know how to disable the internal *91 feature on this phone or have another work around?