Specifications

2-9
TOKEN RING OVERVIEW
Lobe Cable
The lobe cable is used to attach a station the TCU on an MSAU. In practice
lobe cabling can consist of various cable segments constituting the
lobe-to-TCU connections. Segments typically include patch cables from
the TCUs to the main wiring panel, the lengths of the main wiring to the
station locations, and then patch cables from floor/desk sockets to the
stations. Like trunk cable, lobe cabling can consist of either fiber optic or
unshielded or shielded twisted pair copper cable. Lobe cabling is straight-
through with no crossover.
Repeater Circuitry
Repeater circuitry is typically embedded in many concentrator products,
including Media Interface Modules and stackable hubs. It re-times and
regenerates the frame to drive longer distances between stations. Note
also that each station provides the repeater function.
Converters
A repeater that also converts from one media type to another, that is fiber
signals to copper or vice versa.
Wiring Closet
The distribution point for the building wiring, typically consisting of a
number of patch panels. This is the obvious location to place the MSAUs.
Ring In and Ring Out (RI/RO) Ports
RI/RO ports are the connectors on the MSAUs used to interconnect the
units via trunk cabling. The wrap feature is implemented at these
interfaces.
Ring Insertion
For a station to become an active member of the ring it must insert itself
into that ring. It does this by sending a low voltage DC signal to the
MSAU. This signal does not effect the data signal on the lobe cable. For
this reason it is usually referred to as the Phantom Current.
When the phantom drive is received by the MSAU, a relay closes, enabling
the station to insert into the ring. The phantom drive will not be sent if the
station’s hardware adapter has not been initialized by the software.