Phone & SMS Software Downloads: 57 Free and Open-Source Phone & SMS Tools

Phone and SMS software covers instant messaging and voice calls, SMS gateways and text management, phone-to-PC transfer tools, and contact and call-log managers. For messaging look at end-to-end encryption and multi-device sync; for an SMS gateway, whether it needs your own number and whether it is open source. Desktop messaging clients are large downloads, so the button points at the official site.