Fiber optic phone adapter providing secure transmission of telephone conversation over fiber optic link for up to 50 km (31 miles)
Supports single mode and multimode fibers
Available with laser diode option for extended ranges
Supports both DTMF and pulse dialing
Receives power from AC, DC power supply or on-board nickel-cadmium rechargeable battery
Available in two versions:
- Subscriber unit compatible with any standard telephone set
- PBX unit for direct connection to PBX

F-TEL, fiber optic telephone adapter, provides direct, secure fiber optic connection between any telephone set and a PBX, or between two telephone sets.
F-TEL converts the electrical signals into optical signals. Two in-line units are required to complete a fiber link: a PBX unit (F-TEL/CO) for the PBX side and a subscriber unit (F-TEL/SUB) for the subscriber telephone set.
F-TEL operates in two typical configurations:
- Telephone-to-PBX optical connection (subscriber to PBX)
- Telephone-to-telephone optical connection (subscriber to subscriber).
F-TEL is designed to operate with several grades and sizes of fiber optic cable. Use of fiber optic cabling provides immunity to electrical interference such as EMI and RFI.
Three optical interfaces are available:
- 850 nm wavelength for multimode fiber
- 1300 nm wavelength for single mode fiber
- Laser diode (1300 nm) for single mode fiber with extended operating range.
The laser diode has an internal temperature control circuit to compensate for ambient temperature changes.
F-TEL/SUB supports 20 Hz or 25 Hz ringing, as well as DTMF and pulse dialing to meet requirements of national carriers.
As a backup to the standard AC or DC power supply, F-TEL can be powered via an external 9-12 VDC power supply or by an on-board nickel-cadmium rechargeable battery.
LED status indicators are available on the front panel of both units for indicating the system status

F-TEL