IoT Fire Alarm Device Design

flux

You should ask Quectel / supplier for the EC25MXGA hardware design package, not just the marketing datasheet.
Ask for:
  1. EC25MXGA Hardware Design Guide
    • Full pin descriptions
    • Power supply requirements
    • PWRKEY / RESET timing
    • UART / USB / SIM / RF reference circuits
    • VDD_SDIO usage guidance
  2. Recommended PCB land pattern / footprint
    • Pad dimensions
    • Pad numbering
    • Paste mask / solder mask recommendations
    • Keepout zones under/around the module
    • Assembly notes
  3. Reference schematic
    • VBAT_RF / VBAT_BB decoupling
    • SIM socket wiring
    • Antenna matching / ESD
    • Status pins
    • Power-on/off sequence
  4. RF layout guidelines
    • 50 Ω antenna routing
    • Ground stitching via recommendations
    • Antenna connector/matching network placement
    • Diversity/GNSS pins if used or unused
  5. Certification documents
    • RCM / ACMA / AS/CA S042 relevance
    • Carrier approval info for Australia
    • LTE band support for AU carriers
    • Test reports if available
  6. Lifecycle / supply confirmation
    • Active production status
    • Recommended replacement if EC25MXGA is not preferred
    • Minimum order / lead time
Short message you can send:
We are designing a dual-modem Australian fire alarm signalling device using 2 × EC25MXGA. Please provide the EC25MXGA hardware design guide, recommended PCB land pattern/footprint, reference schematic, RF layout guide, SIM interface recommendations, VDD_SDIO connection guidance, Australian carrier/certification documentation, and lifecycle/supply status.
D

drewmoutney

Ok I’ll contact them

flux

Good plan. Ask them specifically for the hardware design guide + recommended PCB land pattern for EC25MXGA-128-SNNS.
Until we get that, the safest path is:
  • Keep EC25MXGA in the design.
  • Do not send the PCB to manufacture yet.
  • Continue with placement/routing cleanup only as a draft.
  • Finalize modem footprint, SIM wiring, RF layout, and VDD_SDIO treatment once Quectel confirms the official guidance.
Clean draft layout
Review EC25 wiring
Check power budget
Update factory checklist
Run current checks
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Telecommunications Compliance Notes — AS/CA S042
User-provided compliance requirement
The cellular subsystem must consider the Telecommunications Technical Standard:
Telecommunications Technical Standard (Requirements for Connection to an Air Interface of a Telecommunications Network – AS/CA S042) 2015
Depending on whether the device is a 2G, 3G, 4G, or satellite device, AS/CA S042-2015 requires compliance with relevant parts including:
  • AS/CA S042.1 — Requirements for connection to an air interface of a Telecommunications Network — Part 1: General
  • AS/ACIF S042.3 — Requirements for connection to an air interface of a Telecommunications Network — Part 3: GSM Customer Equipment
  • AS/CA S042.4 — Requirements for connection to an air interface of a Telecommunications Network — Part 4: IMT-2000 Customer Equipment
Design implications for this project
  • The Quectel cellular modules and final device integration must be assessed against Australian telecommunications connection requirements, not only fire-alarm standards.
  • The final modem choice must have suitable Australian approvals/documentation for the cellular technology used.
  • Antenna ports, external antenna selection, RF exposure, conducted/radiated emissions, SIM interface, and modem firmware configuration can affect compliance.
  • Since the design is intended to use two always-active cellular modems, compliance planning must consider both transmitters, possible simultaneous operation, antenna separation, and enclosure labeling/instructions.
  • Avoid relying on 2G/3G networks for a new design; confirm the exact EC21-AUV supported bands and carrier acceptance for the deployment region.
Compliance documents now relevant
  • AS1670.3 — fire alarm monitoring system/network performance.
  • AS4428.6 — Alarm Signalling Equipment requirements.
  • AS/CA S042.1 — general air-interface connection requirements.
  • AS/ACIF S042.3 — GSM customer equipment, if applicable.
  • AS/CA S042.4 — IMT-2000 customer equipment, if applicable.
  • ACMA requirements and labeling.
  • Carrier/PTCRB/module approval documentation as applicable.
Schematic/layout implications
  • Use manufacturer-recommended Quectel reference design for power, SIM, USB/UART, reset/PWRKEY, RF, and ESD protection.
  • Preserve RF keepouts and 50 Ω controlled-impedance antenna routing.
  • Include RF ESD protection on each external antenna line.
  • Include SIM ESD protection and proper SIM routing.
  • Provide independent modem power control and status monitoring for the two always-active paths.
  • Maintain records of module approvals, antenna type/gain, cable/pigtail details, and RF layout decisions for compliance review.

  • User-provided compliance requirement

  • Design implications for this project

  • Compliance documents now relevant

  • Schematic/layout implications