Transition Networks TR-CF-01 User Manual page 4

MEDIA CONVERTERS in the NETWORK
The fiber standard to which the media converters comply is the approved IEEE 802.5j standard. However,
using a switch setting, the media converter can be adapted to some of the proprietary implementations that
evolved before the standard. This proprietary mode reduces the protocol frequency to 1-10kilohertz.
Token Ring topology combines the physical star with the logical ring. Any break in the Token Ring prevents
transmission of the 'token' on which the Token Ring protocol is based and therefore prevents data
transmission. Token Ring concentrators implement a loopback function which, in the event of a break in the
ring, loops back the ring to isolate the break. Transition Networks Token Ring media converters are designed
to preserve this fault-recovery feature.
Insertion into the Token Ring is always initiated when the station or concentrator Ring-Out port asserts a
phantom voltage onto the twisted-pair line. The media converter detects this voltage and generates an
'insertion key' onto the fiber, then loops back the twisted-pair receive to transmit and the fiber receive to
Active Station to Active Concentrator Lobe Port
2 kilometers - multimode
15 kilometers - singlemode
C/RO S/RI 1 2 3 4
UTP/STP
Fiber
TR-CF-01
Converter Media Fiber
to Pair Twisted Ring Token
Set RJ-45 switch to S/RI. Input DC 9V
Set Switch 1 & 2 to Mode 1.
Set Switch 3 to Active.
Set Switch 4 according to network
803.5j compliance.
C/RO S/RI 1 2 3 4
Set RJ-45 switch to C/RO.
Set Switch 1 & 2 to Mode 2.
Set Switch 3 to Active.
Set Switch 4 according to network
803.5j compliance.
Direction of phantom voltage drive (twisted-pair)
or of 'insertion key' generation (fiber)
transmit. When an 'Insertion Key
Echo' is received on the fiber, the
media converter disables the
loopback and passes the twisted-pair
receive to fiber transmit and the fiber
receive to the twisted-pair transmit.
On the other side of the fiber, the
converter drives phantom voltage
and detect for a valid link and the
fiber and twisted-pair interfaces are
in a loopback state. Upon detecting a
valid link, the fiber and twisted-pair
interfaces disable the loopback.
Thus, the Token Ring path is not
Active Concentrator
opened until a full check from end to
end is done, protecting the integrity
RI RO
of the Token Ring.
Passive Concentrator
RI RO
C/RO S/RI 1 2 3 4
Set RJ-45 switch to C/RO.
Set Switch 1 & 2 to Mode 4.
Set Switch 3 to Passive.
Set Switch 4 according to network
803.5j compliance.
Active Concentrator
RI RO
C/RO
Set RJ-45 switch to C/RO.
Set Switch 1 & 2 to Mode 4.
Set Switch 3 to Active.
Set Switch 4 according to network
Passive Concentrator RO to Passive Concentrator RI
2 kilometers - multimode
15 kilometers - singlemode
UTP/STP
Fiber
TR-CF-01
Converter Media Fiber
to Pair Twisted Ring Token
Input DC 9V
Direction of phantom voltage drive (twisted-pair)
or of 'insertion key' generation (fiber)
Active Concentrator RO to Active Concentrator RI
Direction of phantom voltage drive (twisted-pair)
or of 'insertion key' generation (fiber)
2 kilometers - multimode
15 kilometers - singlemode
S/RI 1 2 3 4
UTP/STP
Fiber
TR-CF-01
Converter Media Fiber
to Pair Twisted Ring Token
Input DC 9V
RI RO
803.5j compliance.
C/RO
Set RJ-45 switch to S/RI.
Set Switch 1 & 2 to Mode 2.
Set Switch 3 to Active.
Set Switch 4 according to network
Passive Concentrator
RI RO
C/RO S/RI 1 2
Set RJ-45 switch to S/RI
Set Switch 1 & 2 to Mode 3.
Set Switch 3 to Passive.
Set Switch 4 according to network
803.5j compliance.
Active Concentrator
S/RI 1 2 3 4
803.5j compliance.
3 4