Cabletron Systems TRMIM-62A, Руководство пользователя

Страница: 16 / 32

REQUIREMENTS AND SPECIFICATIONS
2-2
2.2 MANAGEMENT MODULE REQUIREMENTS
This section lists Token Ring management modules with their firmware
versions required for interoperability with the TRMIM-62A:
Management Module Firmware Version
TRMM/TRMMIM 3.01.01 or greater
TRMM-2/TRMM-4 01.02.01 or greater
TRBMIM/TRBMIM-T 2.03.01 or greater
2.3 CABLING GUIDELINES
Take care in planning and preparing the cabling and connections for the
network. The quality of the connections, the length of cables, and other
conditions of the installation are critical factors in determining the
reliability of the network. Work area wall plates/outlets used for the
network should be clearly labeled as supporting Token Ring network lobe
connections.
2.3.1 Maintaining Port/Cabling Impedance Matching
Impedance matching between TRMIM-62A lobe ports and lobe cable is
an important factor in maintaining optimal performance from the network
installation. Basically, impedance is the total resistance, measured in
ohms, that a circuit offers to electrical data signals. Impedance
mismatches between the coaxial lobe cables carrying Token Ring signal
traffic and the lobe ports to which they are connected precipitate excessive
crosstalk, caused by reflecting waves in the transmission lines.
To avoid degradation of the quality of Token Ring signal transmission in
the network, use only RG 62 93-ohm cable for all lobe port connections to
the TRMIM-62A.
2.3.2 Recommended Lobe Lengths
The length of the cable connecting a station to the trunk coupling unit
(TCU) port on a network module is referred to as the lobe length.
Table 2-1 specifies the recommended maximum lobe lengths per ring
speeds of 4 and 16 Mbps for the TRMIM-62A.