“AllStarLink is a world wide network of Amateur Radio repeaters, remote base stations, and hot spots accessible to each other via the Internet and/or private IP networks. AllStar software runs on a dedicated Linux computer (including the Raspberry Pi) that you host at your home, radio site, clubhouse, school, university, workplace, or computer center. AllStar is based on the open source Asterisk PBX and is released under the GNU GPL and is free for anyone to use. The core of AllStar and AllStarLink is the powerful app_rpt application and associated modules that load into the Asterisk PBX system.”

Allstar Wiki

https://hamprojects.info/shari/

“SHARI (SA818 Ham Allstar Radio Interface) is a ham construction project designed by N8AR that implements a Raspberry Pi hosted Allstar node using a NiceRF SA818 embedded UHF (420 – 450 MHz) or VHF (144-148 MHz) radio module. SHARI is designed as a kit for construction and use in the amateur radio service by licensed amateur radio operators who can assure that their assembled SHARI kit meets FCC mandated operating requirements including RF frequency, deviation and required power levels at the fundamental and harmonic frequencies.”

https://www.node-ventures.com/

ClearNode is a Raspberry Pi based AllStar, EchoLink and Digital Modes (DMR, P25, YSF, FCS, NXDN) simplex node with an integrated low power FM radio transceiver. You can use your analog FM HT to work AllStar, EchoLink and the Digital modes.

https://hamvoip.org/

I recommend using the hamvoip software if you plan on building a raspberry pi node.