Eicon Networks ISDN NT1 Especificaciones descargar pdf (Pagina 50)

the user's local power supply has failed. Contrast this with PS2 where the NT1 provides

this power from its own mains plug.

If none of the equipment that you have connected to your NT1 requires a power supply

through the interface, you do not have to plug the NT1 into the mains.

The NT1, which is not a passive device, normally powers itself from PS1. Only if the NT1

contains a TA (so it is a 'NT1-plus' or 'Super-NT1') or if it can supply power to attached

devices will it need to have a mains power supply.

Some ISDN phones can also be powered from PS1. This allows you to have at least one

working ISDN telephone on your line in the event that your local power supply fails. In

some countries this is a regulatory requirement.

Note that there are no provisions for PS1, PS2 or PS3 in the case of the PRI.

Termination

If any of the cables attached to an NT1 is longer than 75 metres, then both ends of of

both cables require termination.

Terminating the NT1 end of the cable is simple. All NT1s have at least one switch that is

concerned with this. It will be marked "short" and "long" (or the equivalent in the local

language).

Termination at the far end of the cable involves installing two 100Ω resistors across each

of the pairs carrying signals. It is done like this.

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Eicon Networks ISDN NT1 Especificaciones Pagina 50