Sierra RC7620-1 4G Handshake Integration

I have a custom, in-house firmware written entirely in C/C++ that now needs to establish a reliable 4G data link through a Sierra RC7620-1 modem. The goal is simple but critical: once powered, the modem must complete its full handshake, register on the LTE network, raise data service, and pass raw data streams to the firmware without manual intervention.

You will work directly on the initialization sequence (power-up timing, AT command flow, SIM and APN setup, PDP context, error recovery) and expose a clean C/C++ interface that my application layer can call for connect, send, receive, and disconnect. All code must compile on our existing tool-chain and be written with portability in mind; the modem itself is connected over UART.

Deliverables (acceptance criteria)
• Source files and header wrappers that build into our firmware image and perform the complete handshake.
• A concise integration guide explaining any configuration flags, pin states, or timing tolerances.
• A short test routine proving successful attachment and sustained data transmission on a live 4G network (I will supply APN and SIM details).

If you have prior experience with Sierra Wireless AT command sets, PPP or Direct-IP modes, that will be a plus, but solid embedded C/C++ skills and a methodical debugging approach are essential. Let me know your estimated turnaround and any similar projects you have completed.