Motorola 68390 - Vanguard 320 Router, Руководство по установке

Страница: 44 / 106

2-14 Installing Vanguard 320 Hardware
ISDN Termination Resistance
ISDN Termination Resistance
Introduction
This section contains basic information on setting ISDN Termination Resistances. If
you require any additional information on ISDN, refer to the
Vanguard Integrated
Services Digital Network: ISDN Manual (Part Number T0103-06).
Note
Termination options for the Release 6.3 and greater enhanced ISDN BRI ST data
Daughtercards are set in the Configure menu, and are not controlled by switches.
Setting Vanguard
320 S/T ISDN
Termination
Resistance Termination resistance is controlled by a set of switches located on the rear of the
Vanguard 320 S/T ISDN.
For the Vanguard 320 S/T, it is assumed that most configurations will have the unit
as the final device, and so 100
Ω
is the default setting of the termination resistance.
This means DIP switches are set to the down position, as shown in Figure 2-5.
Figure 2-5. Setting Termination Resistance on the Rear Connector
If your Vanguard 320 S/T is not the termination device, set the termination resistance
to Hi-Z.
Note
The Vanguard 320 does not have to be powered off to change the switch settings.
The change takes effect when you change the switch setting.
Wiring
Configurations
Requiring
Termination
Resistance Figures 2-6 to 2-8 show three typical wiring configurations requiring the use of a
terminating resistor. In these diagrams, TR indicates the location of the 100
Ω
Terminating Resistor, and NT1 indicates the ISDN switch.
Figure 2-6. Short Passive Bus Configuration
BRI S
100
Ω
HI Z
BRI S
BRI S
Basic Rate ISDN S/T Daughtercard
Termination Resistance
DIP Switch
VANGUARD 320 S/T
NT1
<=10m
TR TR
Maximum Distance of 250m
Other devices
Apply TR here.
Apply TR here.
(Default setting is
100
Ω
Termination)