4G Voice Gateway With DTMF
Budget: $1,500 – $3,000 NZD
The copper landline in my area is being decommissioned, so I need a self-contained unit that lets existing telephone gear keep working by hopping onto the 4G network instead. The box must take a standard SIM, register with VoLTE, and behave exactly like a PSTN line from the perspective of whatever is plugged into it.
Essential functions
• Voice call support over 4G (VoLTE)
• Precise DTMF send / receive performance
I will be inserting SIMs from Spark, OneNZ and 2Degrees, so make sure the RF section covers their bands and passes their VoLTE profiles. The first priority is a rock-solid 4G solution.
Deliverables
• Schematic, BOM and PCB layout ready for manufacture
• Firmware source and compiled image
• Enclosure design (STEP/STL) suitable for small-batch 3-D print or injection moulding
• One fully tested prototype with RJ-11 FXS port that can place/receive calls and transmit/recognise DTMF without clipping or delay
I will sign off once the prototype demonstrates clean voice quality, error-free DTMF, and stable network registration on all three carriers. Mention the modem or chipset you plan to use (Quectel, SimCom, etc.) and any certifications you can help expedite.
Essential functions
• Voice call support over 4G (VoLTE)
• Precise DTMF send / receive performance
I will be inserting SIMs from Spark, OneNZ and 2Degrees, so make sure the RF section covers their bands and passes their VoLTE profiles. The first priority is a rock-solid 4G solution.
Deliverables
• Schematic, BOM and PCB layout ready for manufacture
• Firmware source and compiled image
• Enclosure design (STEP/STL) suitable for small-batch 3-D print or injection moulding
• One fully tested prototype with RJ-11 FXS port that can place/receive calls and transmit/recognise DTMF without clipping or delay
I will sign off once the prototype demonstrates clean voice quality, error-free DTMF, and stable network registration on all three carriers. Mention the modem or chipset you plan to use (Quectel, SimCom, etc.) and any certifications you can help expedite.