Telephone Disconnect Unit

Model #: TDU-4000

TDU-4000

The TDU-4000 provides protection for phones from being used as clandestine listening devices. The unit electrically disconnects the telephone line from the phone when the phone is in the “on hook” position. During disconnect the telephone line is left open, while the voice path on the phone is grounded. This disables room audio from being transmitted onto the telephone line to prevent any eavesdropping. The phone will only connect to the telephone line when it is in the “off hook” position. The “Off Hook” detect and “Ring” detect signals are also opto-isolated from the phone.

A typical link consists of one TDU-4000 with connections to the POTS line and to the subscriber’s phone. FiberPlex recommends “R” units for high security applications because the units have added shielding and filtering for RFI suppression.

Flexible Mounting and Powering Options

The TDU-4000 is part of the FOI line of products designed for ruggedized mil applications. It is housed in the familiar FOI shielded can enclosure. For standalone applications it can be powered by adding a PSQ‐3909 AC supply or a PSQ‐3920 DC power supply (not included). Optionally, up to 8 FOI units can be mounted on CMA chassis adapters and installed in an RMC‐3101 or RMC‐2101 rack mount chassis. The units are powered redundantly by a common back plane connection.

  • Telephone Disconnect

Compatible with:

  • Standard POTS Telephones
  • STU-III Phones
  • Fax Machines
  • Modems

Units will not allow propagation of signals to Central Office or PBX when phone is on-hook

ELECTRICAL SPECIFICATIONS
 
Min
Typ
Max
Power Requirement Voltage Range (V)
7
9
12
Supply Current (mA)
-
400
-
 
Audio Input Level (dBm)
-
5
-
Load Impedance (Ω)
-
600
-
Frequency Response (±3 dB) (Hz)
200
-
8k
 
Environmental Storage Temperature (°C)
-40
-
85
OperatingTemperature (°C)
0
-
50
 
Interface Connector RJ-11
PHYSICAL SPECIFICATIONS
 
Length
Width
Height
Weight
Case Dimensions Size 3
5.75 in (146 mm)
1.453 in (37 mm)
3.188 in (81 mm)
2 lb (0.9 kg)
oi_TDU-4000.png
Standalone Operation  
PSQ-3909  Standalone AC Power Supply
PSQ-3920 Standalone DC Power Supply
WMA-3002 Wall Mount Adapter
WMA-2001 Wall Mount Adapter with ST Optical Patch
Chassis Mounting  
RMC-3101 3U, 19" Rack Mount Chassis. Holds up to 9 FOI Modules
CMA-3002 Chassis Mount Adapter for RMC-3101 Chassis. (1) per FOI Module required
PSM-3010 Spare Power Supply for RMC-3101
Industrial Solutions
RMC-3700 Environmental Enclosure for FOI Modules
CMA-3002 Chassis Mount Adapter for RMC-3101 Chassis. (1) per FOI Module required
PSM-3010 Spare Power Supply for RMC-3101

How to Buy

We support a variety of clients from multiple markets. To make the buying process the cleanest and most efficient we provide a number of ways to purchase our products.

See our How To Buy page to find the procurment method that works best for you and your business.