Features:
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These CentreCOM Micro Repeaters are two port media converters designed for the Fiber Optic Inter Repeater Link (FOIRL) to coaxial cable media market place. These micro repeaters allow for connection of a FOIRL segment to either a thin (10BASE2) coaxial segment with the AT-MR127F, or to an AUI (10BASE5) coaxial segment with the AT-MR126F. Segments on either side of the unit support full length, fully repeated transmission and allow the maximum number of nodes specified by the IEEE.
These media converters utilize state-of-the-art technologies, including a custom Application Specific Integrated Circuit (ASIC) and Surface Mount Technology (SMT), which provide enhanced functionality, increased reliability, and improved performance.
The CentreCOM Micro Repeaters provide the complete functionality of large repeaters, including packet regeneration and network partitioning. The packet regeneration results in a higher performance network by regenerating preamble, retiming the data packets and extending collision fragments to ensure collision enforcement by all nodes.
The use of a custom ASIC and an internal power supply make the CentreCOM Micro Repeaters compact and easy to install. The units small size allows for the repeater function to be brought to the desktop or used in a wall mount installation.
The AT-MR126F (AUI to FOIRL) and AT-MR127F (BNC to FOIRL) have a selectable switch for full or half repeater mode. In the full repeater mode, each repeater counts toward the total repeater count specified by IEEE 802.3. In certain situations, (i.e. connections between buildings using the FOIRL ports), fully repeated functionality is not needed. The half repeater mode allows a pair of repeaters to count as one repeater linking the two networks together.
Network diagnostic LEDs are provided on the front of the CentreCOM Micro Repeaters to aid in troubleshooting and fault isolation. Both segments have "Transmit," "Receive," "On Line" and "Collision" indicators. All units come with a "Power" and a "Link Integrity Test" LED for the fiber optic ports.
Technical
Specifications 
Front Panel Status Indicators
Per Port: On Line Indicates segment is not auto partitioned Collision Indicates collision detected on the repeater Receive Indicates a packet is being received from the segment Transmit Indicates a packet is being transmitted to the segment
Fiber Optic: Link Indicates a valid link
Central: Power Indicates power is on
Packet Transmission Characteristics
Delay Times: (Any segment in to other segment out) Start of Packet Collision to Jam (Maximum) (Maximum) AUI to FO 975 ns 1175 ns FO to AUI 1225 ns 1175 ns BNC to FO 1100 ns 1250 ns FO to BNC 1050 ns 1000 ns
Preamble: Input Minimum of 38 bits including SFD Output 64 bits including SFD (last 2 bits are 1,1)
Jam Output: A pattern of 1,0 is sent to all segments when a transmit collision is detected. This pattern is also sent to the other segment when a receive collision is detected.
Packet Fragment Extension: 96 bits including preamble. Packet fragments are extended using the (1,0) data pattern.
Auto Partition/Reconnection: Each segment will partition itself from other segments if either 32 consecutive collisions occur or if a collision longer than 1 ms occurs. Reconnection occurs after data is transmitted or received without collision on partitioned port for 512 bit times (IEEE standard algorithm).
Jabber Lock-Up Protection: Packet output is momentarily interrupted for 96 bit times when packet transmission exceeds 64K bits.
Coaxial Interface
Input Impedance > 100K ohm Coaxial Tap Capacitance < 6 pf
Input/Output Voltage: Typical Worst DC Offset -1.03 V -0.93 to -1.12 V AC Offset 2.05 Vp-p 1.4 to 2.25 Vp-p Transmit Rise/Fall Time 25 n 25 ± 5 ns
AUI Interface
Parameter: Typical Maximum Signaling Rate 10 Mbps DI and CI Input Impedance 78 ohm 73 to 83 ohm DO Output Impedance 78 ohm 73 to 83 ohm DO Output Voltage 900 mV 450 to 1315 mV DI, CI Threshold Level 160 to 275 mV AUI Cable Length 50 meters
Fiber Optic Interface
Typical Worst Optical Wavelength 830 nm -20 nm Optical Saturation 170 µW 150 µW (-7.6 dBm) (-8.2 dBm)
Transmitter: Output Power 62.5/125 µM -12.0 dBm -15.0 dBm 100/140 µM -6.5 dBm -9.5 dBm 50/125 µM -16.5 dBm -19.5 dBm
Receiver: Sensitivity -33 dBm (0.5 µW) -30 dBm (1 µW) Saturation -13 dBm (50 µW) -14 dBm (40 µW) Bit Error Rate Better than 10-10
Thin (BNC) Segments
Type: BNC receptacle with gold center contact for use with BNC type plugs and RG58 thinnet cable. Each segment is connected to an internal 50 ohm terminator (externally switchable).
Internal Transceiver: Complies to the IEEE 802.3 standard.
Segment Length: 0 to 185 meters (RG58) terminated both ends. Maximum of 29 other transceivers on any one segment. (Minimum spacing 0.5 meters between transceivers.)
Power Characteristics
Parameter: Input Voltage (Auto Ranging): 100 to 240 VAC, 50/60Hz, 0.25 A
Power: 15 watts (Maximum)
Physical Characteristics
Dimensions 21.0 cm x 11.2 cm x 3.1 cm (8.3 in. x 4.4 in. x 1.3 in.) Weight 480 grams (1 lb. 1 oz.) Temperature Operating 0° to 50° C Storage -20° to 60° C Relative Humidity 5% to 80% non-condensing
Electrical/Mechanical Approvals: EMI FCC Class A Safety UL, CSA, TUV-GS, IEC 825-1 Class 1
Ordering Information
Part Number Port 1 Port 2 AT-MR126F-X1 SMA AUI AT-MR126F-X3 ST AUI AT-MR127F-X1 SMA BNC AT-MR127F-X3 ST BNC
Where "X" = 1 for 110V with U.S. power cord included 2 for 220V without power cord included
Government Ordering Information
Country of Origin Singapore Warranty 1 year
Part # Gov't Part # Description AT-MR126F-13 AT-FMR126F-13 MR126F AUI to F.O. 2 Port Micro Repeater, int. pwr. supply, AT-MR127F-11 AT-FMR127F-11 MR127F BNC to F.O. 2 Port Micro Repeater, int. pwr. supply, SMA AT-MR127F-13 AT-FMR127F-13 MR127F BNC to F.O. 2 Port Micro Repeater, int. pwr. supply, ST