Product Overview
Tone Commander NT1U-100TC: U-Interface In, S/T Bus Out
Condition
New and unused in the manufacturer's carton. The sample photographed here was unpacked for the camera: it came out of a poly bag inside the white Tone Commander box, alongside the wall plug-in power supply in its own inner carton, a gray line cord, and the printed installation instructions. The outer carton shows light scuffing and softened corners from storage, which the photos capture. The unit itself is clean, with the molded front bezel lettering and both LED windows unmarked. More than one is on the shelf, so the photographed piece is representative.
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Product Overview
The NT1U-100TC is a standalone ISDN Network Termination 1, built by Tone Commander Systems of Mukilteo, Washington, with the carton marked Made in USA. Per the installation sheet packed with it, the unit converts an ANSI standard 2B1Q ISDN U-interface arriving from the telco central office into an S/T interface for local customer terminal equipment, and both point-to-point and multipoint ISDN terminal equipment configurations are supported. It complies with ANSI T1.601-1992 and T1.605-1991 interface standards and is compatible with National-1 and National-2 ISDN standards. The rear panel carries a LINE jack, a TERMINAL jack, a DC input marked 6VDC 0.3A, and a TERMINATION slide switch with legends for 50 ohm and 100 ohm; the front bezel carries STATUS and POWER indicators. The installation sheet rates the unit at 6 to 9 VDC, 0.75 watts maximum, 1.1 inches high by 3.3 wide by 5.1 deep, 0.34 pound, 0 to 50 C (32 to 122 F), and 5 to 95 percent non-condensing humidity. It is intended for applications using locally powered terminal equipment; no terminal power is provided on the S/T interface. The wall plug-in adapter shown is a Class 2 transformer labeled AC 120V 60Hz 6W input and DC 6V 300mA output, model 35-6-300, UL listed under file E140898.
Key Features
- Converts an ANSI standard 2B1Q ISDN U-interface to an S/T interface
- Supports point-to-point and multipoint ISDN terminal equipment configurations
- Complies with ANSI T1.601-1992 and T1.605-1991; compatible with National-1 and National-2
- Rear LINE jack, TERMINAL jack, and DC input marked 6VDC 0.3A
- TERMINATION slide switch marked 50 ohm and 100 ohm
- STATUS and POWER indicators on the front bezel
- 6 to 9 VDC operating voltage, 0.75 watts maximum consumption
- 1.1 in H x 3.3 in W x 5.1 in D, 0.34 lb per the installation sheet
- 0 to 50 C operating temperature, 5 to 95 percent non-condensing humidity
- Includes wall plug-in Class 2 adapter (DC 6V 300mA, model 35-6-300, UL file E140898), gray line cord, and printed installation instructions
- Built in the USA by Tone Commander Systems, Mukilteo, Washington
Applications
- A telecom tech keeping a legacy ISDN BRI circuit in service and needing a clean U-to-S/T termination at the customer end
- A broadcast or studio engineer maintaining an ISDN codec setup where the equipment expects an S/T bus rather than a raw U loop
- A PBX or key-system installer swapping a failed NT1 on a customer site without hunting down a bare pull and a mismatched adapter
- A bench or lab running ISDN protocol gear where the TERMINATION switch needs to be set to 50 or 100 ohm to match the wiring
Frequently Asked Questions
What does this unit actually convert?
Per the installation sheet in the photos, it takes an ANSI standard 2B1Q ISDN U-interface coming from the telco central office and presents an S/T interface for local customer terminal equipment. Point-to-point and multipoint terminal configurations are both supported.
Does it power ISDN devices over the S/T bus?
No. The installation sheet states the NT1U-100TC is intended for applications that use locally powered terminal equipment, and that no terminal power is provided on the S/T interface. Anything on the bus needs its own supply.
What comes with it?
The photographed sample came with the NT1U-100TC, the wall plug-in power supply in its own inner box, a gray line cord, and the printed installation instructions, all inside the Tone Commander carton. The photos are the spec for that piece.
Which standards and protocols does it match?
The installation sheet lists ANSI T1.601-1992 and T1.605-1991 interface standards and compatibility with National-1 and National-2 ISDN standards. Anything beyond that is not confirmed - verify against the datasheet before use.
Why buy this one instead of a bare NT1 out of somebody's parts bin?
An NT1 is a one-per-line part, and what you need is one that works. This is a new, unused unit photographed with its power supply, line cord, and instruction sheet, so you can see exactly which configuration you are ordering instead of gambling on a stripped pull with no adapter and no paperwork. Tone Commander built these in Mukilteo, Washington, and the carton still says Made in USA. Shipping is $8 flat rate and goes free once your order passes $28, and orders leave our Idaho warehouse the same or next business day.
Every ISDN line had to end somewhere, and for a lot of them it ended in a third of a pound of Mukilteo-built plastic quietly turning 2B1Q into something the equipment on the desk could talk to. If a circuit on your bench or in your wiring closet still expects that handshake, this one has been waiting in its box for the assignment.
