Daisy-chaining devicemaster up 2e/4-port units – Comtrol UP DeviceMaster Installation User Manual
Page 83
Hardware Installation and Configuration Guide: 2000451 Rev. J
Troubleshooting and Technical Support - 83
Troubleshooting and Technical Support
Daisy-Chaining DeviceMaster UP 2E/4-Port Units
The DeviceMaster UP 2E/4-port models with external power supplies follow the
IEEE specifications for standard Ethernet 10/100BASE-TX topologies.
When using the UP and DOWN ports, the DeviceMaster UP 2E/4 is classified as a
switch. When using the UP port only, it is a simple end node device.
The maximum number of daisy-chained DeviceMaster UP 2E/4 units, and the
maximum distance between units is based on the Ethernet standards and will be
determined by your own environment and the conformity of your network to these
standards.
Comtrol has tested with seven DeviceMaster UP 2E/4 units daisy-chained
together using 10 foot CAT5 cables, but this is not the theoretical limit. You may
experience a performance hit on the devices at the end of the chain, so it is
recommended that you overload and test for performance in your environment.
The OS and the application may also limit the total number of ports that may be
installed.
Following are some quick guidelines and URLs of additional information. Note
that standards and URLs do occasionally change.
•
Ethernet 10BASE-T Rules
-
The maximum number of repeater hops is four.
-
You can use Category 3 or 5 twisted-pair 10BASE-T cables.
-
The maximum length of each cable is 100m (328ft).
Note: Category 3 or 5 twisted pair cables look the same as telephone cables
but they are not the same. The network will not work if telephone
cables are used to connect the equipment.
•
Fast Ethernet 100BASE-TX rules
-
The maximum number of repeater hops is two (for a Class II hub). A Class
II hub can be connected directly to one other Class II Fast Ethernet hub. A
Class I hub cannot be connected directly to another Fast Ethernet hub.
-
You must use Category 5 twisted-pair 100BASE-TX cables.
-
The maximum length of each twisted-pair cable is 100m (328ft).
-
The total length of twisted-pair cabling (across directly connected hubs)
must not exceed 205m (672ft).
Note: Category 5 twisted pair cables look the same as telephone cables but
they are not the same. The network will not work if telephone cables
are used to connect the equipment.
•
IEEE 802.3 specification: A network using repeaters between communicating
stations (PCs) is subject to the 5-4-3 rule of repeater placement on the
network:
-
Five segments connected on the network.
-
Four repeaters.
-
Three segments of the 5 segments can have stations connected. The other
two segments must be inter-repeater link segments with no stations
connected.
Additional information may be found at
searching the web.