JK-DTMF FC7.820.506

The JK-DTMF FC7.820.506 (commonly version V1.1) is the sister board to the FC 7.820.507 you previously asked about. While the .507 board acts as the main controller, the JK-DTMF is a specialized module designed specifically for Dual-Tone Multi-Frequency (DTMF) signal processing.

Technical Function

In a telephone exchange system (PBX), this board is responsible for:

• Tone Recognition: Decoding the frequencies generated when a user presses buttons on a telephone keypad.

• Signal Translation: Converting those audio tones into digital commands that the main controller (the .507 board) can use to route calls or trigger system functions.

• Command Processing: Managing “touch-tone” dialing and IVR (automated menu) interactions within the exchange.

Key Specifications

Use in Marine/Industrial Systems

These boards are often found in integrated internal communication systems on large vessels or in older industrial facilities. They are built to high industrial standards, which is why they are still traded in the surplus market for high prices (often $500–$800 USD) to keep legacy systems operational.

Comparison: .507 vs .506

• FC 7.820.507 (JK-TONE): The “brain” or main logic controller of the exchange.

• FC 7.820.506 (JK-DTMF): The “ears” of the system, specifically handling the keypad tones and dialing signals.

Finding a Replacement

If you are repairing a system that uses both:

1. Look for Version Matches: Ensure you are replacing a V1.1 with a V1.1.

2. Verify the Seller: Since these are niche parts, they are mostly sold by specialized marine electronics or industrial automation surplus vendors (common in India and Southeast Asia).

3. Inspect for Heat Damage: In these specific units, the logic chips can sometimes fail due to voltage spikes in the communication lines.