Overview
The Western Electric MMI-7217 is a precision analog panel meter combining DC voltage and milliampere measurement capability in a single compact instrument. Rated at 333 ohms impedance with designation D9A, this meter was designed for reliable performance in demanding electrical test and measurement applications. Built by Western Electric—a trusted name in telecommunications and industrial instrumentation—the MMI-7217 continues to serve technicians and engineers in legacy systems and vintage equipment maintenance.
Key Features
- Dual-function measurement: DC volts and milliamperes in one meter
- 333 ohms impedance rating for accurate circuit measurement without excessive loading
- Analog needle display for direct, intuitive readings
- Robust panel mount construction for industrial and laboratory use
- USA-manufactured Western Electric quality and durability
- Suitable for telecommunications, communications network testing, and electrical maintenance
Technical Specifications
- Manufacturer: Western Electric
- Model: MMI-7217
- Impedance: 333 ohms
- Meter Type: DC Voltmeter / DC Milliammeter
- Designation: D9A
- Display Type: Analog needle gauge
- Mounting: Panel mount
- Origin: USA manufactured
Typical Applications
- Telecommunications and telephone exchange testing
- Communications equipment measurement and troubleshooting
- Electrical circuit verification and maintenance
- Vintage and legacy equipment diagnostics
- Educational demonstrations in electrical labs
- Test benches for DC voltage and current verification
Compatibility & Replacements
Compatible With
- Legacy telephone switching and communications systems
- Vintage Western Electric test sets and diagnostic equipment
- Standard 12V, 24V, and 48V DC industrial circuits
- Laboratory test benches and maintenance workstations
Replaces / Drop-In Replacement For
- Compatible with other Western Electric MMI series panel meters in legacy telephone exchange applications
- Verify specific circuit requirements and measurement ranges with your system documentation before substitution
Works With
- Any system requiring DC voltage measurement from 0–70 volts (typical range)
- Telecommunications legacy networks and heritage systems
- Analog meter-based measurement and monitoring architectures
