GarrettCom 8000X User Manual
Page 21
Magnum 8000X Mixed-Media Fiber Hubs Installation and User Guide (05/ 02)
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SPM-FDSSC’s can be used together on each end of a fiber segment to get the
maximum distance of 15km of single-mode fiber optic cable in a Fast Ethernet
network. For an SPM-FDSSC used to connect into a separate collision domain,
the cable distances and hop-counts allowable would have to be calculated
taking into account all the devices’ Path Delay Values (PDVs) that are part of
that domain.
An SPM operating at 100Mbps has a PDV of 50 BT, i.e., the same PDV as a
DTE or NIC card in a Fast Ethernet collision domain.
2.5.4 Magnum SPM-TTX
The Magnum SPM-TTX is a 10 Mbps or 100Mbps device equipped with
one RJ-45 port which supports either 10BASE-T and 100BASE-TX. The
10/100 speed selection is done with a manual switch on
the unit to prevent ambiguity where it may be used with
other devices such as NICs that are auto-sensing.
The SPM-TTX filters and forwards packets, maintains
its address tables, and segments the network when used as a
10BASE-T or a 100BASE-TX switch port. See Sections 2.5 and
2.5.1 for a general description of an SPM. The SPM-TTX
includes an up-link switch to allow for connection to either user
nodes or for cascaded up-link connections to other hubs. The
attached devices may be either 10 Mb or 100Mbps.
The Magnum SPM-TTX has two LED’s - LINK and
RX - to allow monitoring of link and packet reception status of the SPM’s operation.
2.5.5
SPM Specification Summary Table
(See also “Specifications - SPMs,” Section 1.3)
Magnum SPM-TTX
10
0
10
M
b
/s
U
P
L
IN
K
R
X
L
IN
K
Connector
Standard
Mb/s
Traffic
Pkt Buffer
Address
SPM-FDST
Fiber-ST
100BASE-FX
100/200 full-duplex
1MB
8K total
SPM-FDST
Fiber-SC
100BASE-FX
100/200
full-duplex
1MB
8K total
SPM-SSC
Fiber-SC
100BASE-FX
100/200
full-duplex
1MB
8K total
SPM-TTX
RJ-45
10BASE-T & 100 -TX 10 or 100 shared
256KB
1024/port