Overview
1
Overview
CentreCOM Micro Repeaters are two-port media converters designed for
Ethernet coax network segments. CentreCOM Micro Repeaters support full
length segments on either side, fully repeated transmission and the maximum
number of nodes specified by the IEEE. Repeating packets 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
AT-MR125D is shown in Figure 1.
Figure 1:
AT-MR125D Front and Back Panels
The
AT-MR125D
allows for connection of a thin (10BASE2) coaxial segment.
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 use of a proprietary ASIC has permitted Allied Telesyn to make
the CentreCOM Micro Repeaters exceptionally compact while providing the
complete functionality of large repeaters. The small size of the units allows for the
repeater function to be brought to the desktop or used in a wall mount installation.
Network diagnostic indicators are provided on the front of the micro repeaters to
aid in troubleshooting and fault isolation. Each port has LEDs appropriate for the
medium. For example, on the AT-MR125D, both ports have Transmit, Receive, On
Line and Collision indicators.
Cabling
10BASE2 (Thin Coax) Connections
The micro repeater 10BASE2 thin Ethernet connections support a full 185 meters
(606 ft.) of thin Ethernet coaxial cable. This coax segment will allow up to 30 Media
Access Units (MAU) or transceiver connections including the connection to the
CentreCOM Micro Repeater. The BNC coax connector may be plugged directly
into the BNC connection without using a BNC-T connector and external 50
Ω
terminator. The termination is built in. If the micro repeater is not on either end of
the segment, then the internal 50
Ω
termination must be disabled via the external
switch located next to the BNC connector.
POWER
MR125D
IEEE 802.3 MICRO REPEATER
PORT 1: 10 BASE 2
ON LINE
COLLISION
TRANSMIT
RECEIVE
ON LINE
TRANSMIT
RECEIVE
PORT 2: 10 BASE 2
COLLISION
10 BASE 2
PORT 2
+
–
DC INPUT
10 BASE 2
PORT 1
MR125D
IEEE 802.3 MICRO REPEATER
OFF
ON
TERMINATOR
OFF
ON
TERMINATOR
MR125DBook Page 1 Wednesday, August 21, 1996 4:24 PM
