Table of Contents
The Model 279/279A provides
transparent conversion between fiber optic devices utilizing multi-mode fiber
and those using single-mode fiber. While single-mode fiber can transmit data
over much longer distances than multi-mode fiber, each type has its advantages.
Multi-mode fiber is well suited to the short distances typical of an
installation within a building as opposed to the single-mode variety which is
ideal for longer "metropolitan distances."
Multi-mode: 850 nm, full duplex
2.3 Data Rate
Model 279: 0 to 2.5 mbps
2.4 Loss Budget
15dB max @ 1300 nm on 9/125 um cable
Line Loss: Adjusts to best performance of single-mode fiber
for losses of 2, 5, 10 or 15 dB.
TD and RD LED's and Line-Loss selection LED's
+12 VDC. Supplied by wall-mount adapter, 110 V -
60 Hz standard, 220 V - 50 Hz optional. A DC adapter Model 1510-0037 is also
available that allows operation from a DC source whose voltage is within the
range of +18 VDC to +36 VDC.
7 in W x 3 in H x 1 in D (177.8 mm x 76.2 mm x
Operating temperature: 0o to +50o C
3.1 Physical Mounting
The Model 279/279A can be mounted in any position. Care should be exercised when routing the fiber optic cables. The minimum bend radius of 2 in for the cables should not be exceeded. The Model 279/279A is provided with two mounting holes to allow the unit to be attached to any position.
The Model 279/279A is designed
to interface between single-mode and multi-mode fiber systems. You must have a
Model 279/279A at each end of the single-mode fiber cable. Cables used to attach
to the Model 279/279A should be terminated with ST connectors. Power for the
Model 279/279A is derived from the supplied wall adapter. This power supply is
plugged into the Model 279/279A using the 1.3 mm power jack.
In fiber optic systems that do not offer DC response there usually is a clock signal which is always being transmitted. The presence of this clock signal allows automatic gain-control circuitry to adjust the gain of the receiving amplifier to compensate for single-mode cable loss. Because the Model 279 can operate at DC, it is necessary to establish a different method to compensate for the length of the single-mode cable. In the Model 279 this is accomplished using a four-position switch, labeled "Line Loss" to allow selection of amplifier gain to accommodate single-mode cable losses of 2, 5, 10 and 15 dB. These losses approximate cable lengths of 3, 7.5, 15 and 26 k, respectively. The method of setting the switch is as follows:
1. With the Model 279 installed, set the "Line Loss" switch to a position where the received data is no longer detectable.
2. Position the switch to the previous dB loss position. Because the switch position is not apparent, the selection is indicated on the LED display.
Note: The functions of TD (transmit data) and RD (receive data) are arbitrary, depending on the users implementation; therefore, the data LED's are not marked.
The following is a list of
possible problems that may arise during the installation:
If the Model 279/279A is functioning correctly, any data entered on the keyboard should appear on the screen.
Power for the Model 279/279A is
supplied by a wall adapter that generates +12 VDC. The wall adapter is available
for 110 V, 60 Hz or 220 V, 50 Hz. The part numbers are:
Assistance can be obtained by visiting our Technical Support Center.
TELEBYTE warrants the equipment to be free from defects in material and workmanship, under normal and proper use and in its unmodified condition, for 12 months, starting on the date it is delivered for use. TELEBYTE's sole obligation under this warranty shall be to furnish parts and labor for the repair or replacement of products found by TELEBYTE to be defective in material or workmanship during the warranty period. Warranty repairs will be performed at the point of manufacture. Equipment approved for return for warranty service shall be returned F.O.B. TELEBYTE factory and will be redelivered by TELEBYTE freight prepaid, except for non-continental U.S.A. locations. Non-continental deliveries will be sent COD freight plus import/export charges.
The above warranty is in lieu of all other warranties, expressed or implied, statutory or otherwise, including any implied warranty of merchantability or fitness for a particular purpose. TELEBYTE shall not be liable for any damages sustained by reseller or any other party arising from or relating to any equipment failure, including, but not limited to consequential damages nor shall TELEBYTE have any liability for delays in replacement or repair of equipment.
Out of warranty equipment may be returned to the Greenlawn, NY customer service facility prepaid as described above. Return shipping charges will be billed to the customer. The repaired unit will have a 90-day warranty. In those cases where "NO TROUBLE" is found, a reduced charge will be billed to cover handling, testing and packaging.
Whether in or out of warranty, a Return Material Authorization (RMA) number is necessary. Assistance can be obtained by visiting our Technical Support Center.