82
■
For Personnel Attending to ISDN Line Work
To perform connection work between the rosette and this unit, a certificate is required for the Telephony Working Personnel
Qualification, Digital Class 1 or Class 2. Please ask the telecom or its sales agent for the cabling work. When multiple con-
nectors are connected to a single DSU, the following points must be kept in mind:
• For connectors permissible for bus connections, a maximum of 8 units can be connected to a single DSU.
• The rosette or the connector located at the farthest end from the DSU should be terminated at the termination resistance
(of 100
Ω
).
• The connection distance from the rosette to a connector shall be 10 meters or less.
It is recommended to use a 8-pin modular cable for connection, which is attached to this unit.
The distance to the connector may change according to the size of the cable to be used.
• Confirm the polarity of the ISDN line. Correct wiring should be carried out for the polarity. In particular, it is necessary to
be sure not to reverse the polarity between the rosettes.
• After the completion of cabling work, continuity testing shall be carried out with the aid of an exclusive testing machine.
In some cases, continuity checks with a circuit tester or checking by ISDN telephoning may be insufficient.
• In the case of bus connections for this unit and other connectors to the same ISDN line altogether, there may be an
incoming call to another connector or ringing may take place in an unexpected place. (Including the case when DSU-
incorporated connector adapter is used, or when using a unit connected to a connector-adapter-incorporated analog
port.) In such a case, each connector should be provided with a sub-address or a dial-in service should be used. To use
a dial-in service, another contract is required.
• Use of sub-addresses
- Set sub-addresses for all units that are located on the same ISDN line, and turn on the called number checking func-
tion.
- When a connector adapter is used, settings should be made for “no global incoming call.”
- Prior to originate a call, attach the sub-address of the unit to be called on the dispatchers.
• Use of dial-in service
If an individual number is attached to each connector located on the same line based on the ISDN contract or PBX set-
ting, then the specific connector can be called up by dialing its number.
- Give a dial-in number to each connector.
- Turn on the incoming number checking function.
- When a connector adapter is used, make setting for“no global incoming call.”
DSU
ISDN line
Rosette
Termination
(Terminating resistance 100
Ω
)
10 m or less
AV Codec, etc.
Terminal
Terminal
Terminal
Terminal
Bus connection enabled for a maximum of 8 units
APPENDIX
