AT-MR415T and AT-MR815T Installation Guide
11
10Base-T Cable
The AT-MR415T/AT-MR815T Micro Repeater supports full-length, fully
repeated transmission and maximum node attachments which, for the UTP
link, enables transmissions up to 100 meters (328 ft.).
A serious problem exists concerning identification of modular cable. There are
various grades of voice-quality and data-quality cables available. These can
appear to be similar, but their high-speed data transmission characteristics
are radically different.
One reason for the identification problem the fact that some suppliers have
sold purportedly data-quality cables manufactured with voice-quality cabling.
Data movement will be slow, collision-prone or even non-existent, if voice-
quality cable is used in a 10Base-T network system. To confuse the issue even
further, the LINK LED indicators on the front panel will usually indicate a
valid link in such a case.
For the foregoing reasons, it is vital that all cabling used with 10Base-T
connections is of Level 3, 4, or 5. In most cases, if a cable type is flat, it is
typically not twisted and can cause problems. Generally, cable that is more or
less round in section, gives better results.
The five common modular cable specifications and their applicability to
10Base-T network use are shown in Table 2.
Table 2: Twisted Pair Cable
Cable
Level
Cable
Description
AC Character
Specification
Twist/
Foot
10Base-T
OK?
1
Unshielded
Untwisted
N/A
CCITT
None
NO!
2
Individual
UTP
100
Ω ±
30
Ω
RS232 1BASE5
AT&T PDS
None
NO!
3
Typical Indi-
vidual UTP
100
Ω ±
15
Ω
T1, AT&T ISDN
10Base-T
IBM Type 3
3-5
YES
4
Enhanced
Individual
UTP
100
Ω ±
30
Ω
EIA, TIA
10Base-T
NEMA
5-8
YES
5
Individual
STP
100
Ω ±
30
Ω
EIA, TIA
10Base-T
8-10
YES
