Справочник Пользователя для 3com SuperStack II

A

PPENDIX

 D: C

ONNECTORS

 

AND

 C

ABLES

The WAN connector can be an ISDN S/T (model 43x and 53x), ISDN U 
(model 44x and 54x), 56/64 Kbps CSU/DSU (model 45x and 55x), or 
T1/FT1 CSU/DSU (model 46x and 56x) connector, depending on the 
interface module installed.

To connect a model 43x or model 53x bridge/router to an ISDN network, 
use a Category 5 shielded twisted-pair cable with an RJ-45 connector on 
both ends. 3Com does not supply this cable.

Table 23   Maximum Cable Length in Example Collision Domain Diameters

No Repeaters
(see Figure 22)

not applicable

not applicable

One Class 1 repeater

*

200 m — 100 m max. on 
each side of the repeater

100 m max. TX

Remaining length of FX

231 m 

100 m max. T4 

Remaining length of FX

One Class 2 repeater

†

200 m — 100 m max. on 
each side of the repeater

100 m max. TX

Remaining length of FX

‡

100 m max. T4

Remaining length of FX

Two Class 2 repeaters
(see Figure 24)

205 m — 100 m max. per 
cable span

105 m max. total TX, 100 
m max. per TX cable span

Remaining length of FX

105 m max. total T4, 100 
m max. per T4 cable span

Remaining length of FX

*  A high-delay repeater as specified in IEEE 802.3 standards. A Class 1 repeater usually connects dissimilar media, for instance, UTP to 

fiber.

†  A low-delay repeater as specified in IEEE 802.3 standards. A Class 2 repeater usually connects similar media, for instance, UTP to UTP.
‡ This scenario is unlikely, because Class 2 repeaters do not usually connect FX to T4.