Introduction
This manual provides essential information for the proper setup, operation, and maintenance of your Solid Signal Eartec UL4D Ultralite Full Duplex Wireless Headset System. This system is designed for simultaneous, hands-free communication among up to four users, operating on a 1.9 GHz frequency for clear, interference-free communication. It features noise-canceling microphones with an auto-mute function and a wireless range of up to 1,000 feet line-of-sight.
Package Contents
Your Eartec UL4D Ultralite Wireless Headset System package includes the following components:
- 1 ULDM Dual-Ear Main Headset: This is the primary headset for the system.
- 3 ULDR Dual-Ear Remote Headsets: These are the secondary headsets that connect to the main headset.
- 4 Rechargeable Lithium Batteries: For powering the headsets.
- 10 Bay Multi-port Charger: For recharging the lithium batteries.
- Softside Case: For convenient storage and transport of the system.
- Solid Signal Cleaning Wipes: For maintaining the cleanliness of your headsets.

Image: Eartec UL4D Ultralite Wireless Headset System showing one main dual-ear headset and three remote dual-ear headsets.

Image: Four rechargeable lithium batteries, essential for powering the headsets.

Image: A 10-bay multi-port charger for simultaneously recharging multiple headset batteries.

Image: A softside carrying case designed to store and protect the headsets and their accessories.

Image: A pack of Solid Signal cleaning wipes for hygiene and maintenance.
Setup
- Charge Batteries: Before first use, fully charge all lithium batteries using the provided 10-bay multi-port charger. Ensure the charger indicates a full charge (e.g., green LED).
- Insert Batteries: Insert a charged battery into each headset. Ensure proper orientation according to the battery compartment markings.
- Power On: Turn on the main headset (ULDM) first, then power on the remote headsets (ULDR). The headsets should automatically connect.
- Wearing the Headset: The dual-ear headsets are designed for comfort. The microphone boom can be pivoted to either the left or right side, depending on user preference.
Operating Instructions
- Power On/Off: Press and hold the power button on each headset to turn it on or off.
- Volume Control: Use the volume up (+) and volume down (-) buttons located on the headset to adjust listening levels.
- Microphone Mute: To mute your microphone, pivot the microphone boom upwards. The microphone will automatically unmute when pivoted back down to the speaking position.
- Communication: The system provides full-duplex communication, allowing all four users to speak and listen simultaneously without pressing buttons.
Maintenance
- Cleaning: Use the provided Solid Signal Cleaning Wipes to regularly clean the headset ear cups and microphone foam. Avoid using harsh chemicals or abrasive materials.
- Battery Care: To preserve battery life, remove batteries from headsets when not in use for extended periods. Rechargeable lithium batteries can drain quickly if left in the headset, even when powered off.
- Storage: Store the headsets and all accessories in the softside case to protect them from dust, moisture, and physical damage.
- Water Resistance: This product is Not Water Resistant. Avoid exposure to water or excessive moisture to prevent damage.
Troubleshooting
- No Connection: Ensure all headsets are powered on and within the 1,000 ft line-of-sight wireless range. Check battery levels. If connection is intermittent, try powering off and on again.
- Poor Voice Clarity: Ensure the microphone boom is properly positioned near your mouth. Check that the microphone is not muted (pivoted upwards). High-noise environments are managed by the noise-canceling microphone, but extreme noise may still affect clarity.
- Short Battery Life: Ensure batteries are fully charged before use. Remove batteries from headsets when storing to prevent unexpected drainage.
Specifications
| Item Model Number | UL4D-BUNDLE |
| Brand | Solid Signal (Manufacturer: Eartec) |
| Color | Dual |
| Number of Channels | 4 |
| Special Feature | Microphone Included, Noise Cancellation |
| Frequency Range | 1.9 GHz |
| Talking Range Maximum | 1000 Feet (Line of Sight) |
| Water Resistance Level | Not Water Resistant |
| Compatible Devices | Wireless-capable Devices |
| Battery Life | Up to 6 Hours (per charge) |
Warranty and Support
For warranty information or technical support, please contact Solid Signal directly. Refer to your purchase documentation for specific warranty terms and contact details.