Key Technical Specifications
- Product Model: DL-1200/RTU
- Manufacturer: GE (General Electric)
- Product Type: Power Modem / RTU Communication Module
- Line Transmission Rates: 300, 600, 1200 BPS (Selectable)
- Terminal Rate: Up to 115.2 KBPS
- Modulation Method: Binary Frequency Shift Keying (2FSK)
- Supported Protocols: Bell 102/103/202, CCITT V.21/V.23, DL Standard
- Communication Modes: Half-duplex, Full-duplex, 2-wire, 4-wire
- Output Impedance: 600Ω
- Power Supply: AC 165-265V or DC 220V / -48V
- Error Rate: ≤ 1 × 10⁻⁵ (at SNR ≤ 16dB)
Product Introduction
The GE DL-1200/RTU is a dedicated power modem card designed specifically for Remote Terminal Units (RTUs) requiring reliable, low-speed data communication. It utilizes Binary Frequency Shift Keying (FSK) to transmit serial data over leased telephone lines, microwave, or power line carrier audio channels.Engineered with a dedicated audio FSK chipset, this module avoids the standard voice band (0.3-2.7 kHz) by using upper audio frequencies like 2850 Hz and 3150 Hz. (This frequency separation prevents interference with voice communications sharing the same 3.4 kHz channel.) It supports both CDT cyclic and polling communication standards, making it a staple in legacy SCADA infrastructure.
Installation & Configuration Guide
Preparation (10 min)
Power down the RTU chassis and discharge all capacitors. Identify the target slot and locate the DIP switch chart for your required baud rate (300/600/1200 BPS).Removal (5–10 min)
Release the front panel ejector levers. Pull the module straight out. Always take a high-resolution photo of the DIP switch settings before removal. (I once lost 30 minutes troubleshooting a module that worked perfectly, only to realize I forgot to copy the jumper settings from the old board.)Installation (10 min)
Align the DL-1200/RTU with the backplane guides. Push firmly until the locking mechanism engages. Re-apply the exact DIP switch configuration recorded earlier. Connect the 2-wire or 4-wire audio interface cables securely.Power-On & Test (10 min)
Restore power to the RTU. Observe the module’s status LEDs. Initiate a loopback test or poll the RTU from the master station to verify data integrity. Check for abnormal heat or burning smells.
Troubleshooting Quick Reference
| Symptom | Probable Cause | Probability | Quick Check | Action |
|---|---|---|---|---|
| No carrier / No link | Audio line failure or mute | 80% | Measure audio level at modem terminals | Verify line voltage (0 to -40dB range) |
| High bit error rate | Line noise / Low SNR | 70% | Check SNR (Must be ≥ 16dB) | Lower baud rate or install line filter |
| Comm handshake fails | DIP switch mismatch | 90% | Compare switches to photo / manual | Reprogram switches and cycle power |
| Module overheats | Internal power supply fault | 50% | Check ambient temp and ventilation | Replace module if chassis fan is operational |
| Intermittent drops | Ground loop / Impedance mismatch | 60% | Verify 600Ω termination | Check wiring for proper 2-wire/4-wire config |
Dimensions, Mounting & Wiring Notes
- Dimensions: Standard RTU card form factor (Compatible with Harris RTU slots).
- Mounting Method: Backplane insertion with front panel ejector levers.
- Terminal Notes: Audio interface requires proper 600Ω impedance matching. Ensure shielded twisted pair is used for audio lines to prevent FSK signal degradation.
FAQ
Will this DL-1200/RTU drop into my Harris RTU chassis?
Yes. The DL-1200/RTU card is specifically designed to be mechanically and electrically compatible with standard Harris RTU chassis slots. However, always verify your specific RTU model’s backplane revision before ordering.I swapped the modem but the master station can’t poll the RTU. What gives?
Check your DIP switches first. I’ve replaced dozens of modems only to find the baud rate was set to 300 instead of 1200. Verify the switch settings against the protocol standard (Bell vs. CCITT) required by your master station.Are these new or refurbished?
We stock both New Surplus and Refurbished (Tested) units. All refurbished units undergo our strict 5-step testing protocol, including 24-hour load testing and audio signal verification. We clearly label the condition on every product page.What’s the lead time if you don’t have it in stock?
For legacy power modem cards, sourcing can take 2 to 6 weeks depending on global availability. If you have a critical SCADA communication failure, contact us immediately. We maintain relationships with global surplus networks and can often locate hard-to-find modules faster than standard channels.Can I use this for full-duplex data transfer?
Yes, the DL-1200/RTU supports both half-duplex and full-duplex communication, as well as 2-wire and 4-wire configurations. The mode is selected via the onboard DIP switches. Verify your line topology before configuring.Do you offer a warranty on legacy parts?
Yes. All units come with a 12-month warranty covering manufacturing defects and functional failures under normal operating conditions. We stand behind our testing process. If it fails our test criteria, it doesn’t ship.
