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Model 278X - Card Mounted T1/E1 Fiber Optic Modem
Features

  • T1 DSX-1 or E1 G.703 Interfaces
  • Single/Multimode Fiber Optics
  • 850nm & 1300nm
  • Line Loopback & Fiber Loopback Modes
  • Intensive Diagnostics
  • Local Alarm Contacts
  • Rack Mount Complement of 78X Series


Product Description

The 278X Series of fiber optic modems provide an extremely reliable, high performance alternative for extending T1 or E1 circuits over fiber cables. The series also includes both multimode and singlemode versions. Advanced silicon circuits provide comprehensive error checking and diagnostics. The model number assignments for the rack mount versions are as follows.

Model
No.
Description Mode Wavelength
nm
Connectors Link Budget
dB
2780 T1 to Fiber Multi 850 ST 15
2781 T1 to Fiber Single 1300 ST 10
2782 E1 to Fiber Multi 850 ST 15
2783 E1 to Fiber Single 1300 ST 10
2784 T1 to Fiber Single 1300 FC 14.8
2785 E1 to Fiber Single 1300 FC 14.8


The multimode units are compatible with multimode fiber and support fiber distances of up to 3.5km. The singlemode units, the Models 2781 and 2783, provide the same functional performance, but, are compatible with single-mode fiber cables and offer operation over distances of 15km.

The Models 2784 and 2785 are available with FC connectors and enhanced performance due to the optics, and offers operation over distances of 29km. The FC option requires special ordering.

All of the above units are available in a standalone configuration as the Models 780, 781, 782, 783, 784 and 785 respectively. The card cage rack for the 278X modules is the Model 2200 and it is available with either single or dual redundant power supplies for 110/220 Volt Ac, 50/60 Hz, or -48 Volts DC. The arrangement of model numbers is shown below.

Model No. Description Input Power Redundant
2201 Card Cage-16 Modules 110/220, 50/60 Hz No
2202 Card Cage-16 Modules 110/220, 50/60 Hz Yes
2203 Card Cage-16 Modules -48 Volts, DC No
2204 Card Cage-16 Modules -48 Volts, DC Yes


Data encoding used on the 278X Series consists of converting the incoming AMI, B8ZS or HDB3 to a format suitable for fiber optic communication. A proprietary coding scheme is used which combines the input clock and data into a composite signal which is then transmitted over the fiber. At the receiver this composite signal is then separated the respective signals and back into their respective formats.

This coding technique provides a composite data pulse for each incoming data bit. This insures that the original timing information for each bit is transferred and can be recovered. Decoding long zero runs in the AMI code does not rely on timing interpolation between the transfer of AMI ones. The leading edge of all data bits is synchronous to the input and output data clock. Since the composite fiber data stream utilizes this scheme, no synchronizing headers are required which results in faster recovery from loss of signal data errors as well as guaranteeing true data and timing transparency.

Applications

Applications for the Series 278X modems include extending T1/E1 transmission distance for LAN or video conferencing connecting distributed channel bank networks or providing error free Internet service from a local ISP. The attributes of the fiber transmission line are data security, total electrical isolation, lightning/surge protection and EMI/RFI immunity. These attributes, in addition to the continuous reduction in fiber cable and connectors are compelling reasons to employ fiber transmission links.


Model Description Price Product Info
2780 Card Mounted T1/E1 Fiber Optic Modem $580

Specifications Manual Application Note

2781 Card Mounted T1/E1 Fiber Optic Modem $885

Specifications Manual Application Note

2782 Card Mounted T1/E1 Fiber Optic Modem $580

Specifications Manual Application Note

2783 Card Mounted T1/E1 Fiber Optic Modem $885

Specifications Manual Application Note

2784 Card Mounted T1/E1 Fiber Optic Modem $1280

Specifications Manual Application Note

2785 Card Mounted T1/E1 Fiber Optic Modem $1280

Specifications Manual Application Note

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Bomara Associates Phone: 800.5BOMARA (800.526.6272) Phone: 978.452.2299 Fax: 978.452.1169 3 Courthouse Lane, Chelmsford, MA 01824 USA
Phone: 800.5BOMARA (800.526.6272)

Phone: 978.452.2299

 

Fax: 978.452.1169

Email: bobr@bomara.com

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