Hayes Microcomputer Products DIVA T/A - Manual (Page 78)

DIVA T/A PC Card User’s Guide 78
Appendix A: ISDN Line Termination
This section applies to S/T interface users in Australia and North
America, and provides instructions to help set up termination
scenarios. Termination requirements vary according to: the number of
devices connected to the external NT1; and the distance between the
devices and the external NT1.
Installing a Terminating Resistor
In some cases you may need to install a 50-ohm or 100 ohm
terminating resistor. The diagram below shows you correct way to
install the resistor.
Single ISDN Device
If the external NT1 is connected to a single ISDN device (e.g. DIVA
T/A), follow the instructions below.
75 meters or more
If the connection spans 75 meters (250 feet) or more, connect the 100-
ohm terminating resistor included with the S/T interface cable. Set the
external NT1 to provide 100 ohms of resistance. Consult the manual
provided with the external NT1 for more detailed instructions.
Note: Some external NT1s do not support connections over 75 meters
(250 feet). Check your user documentation to determine the distance
supported.
75 meters or less
If the connection spans less than 75 meters (250 feet), set the external
NT1 to 50 ohms of resistance, and do not connect the terminating
resistor. Consult the manual provided with the external NT1 for more
detailed instructions.