Network information
64
SmartNode 1000 and 2000 Series Getting Started Guide
3 • Planning the installation
Note
Only the one device at the end should be terminated: SmartNode interfaces
are internally terminated at 100 ohms.
It is recommended that a screened cable be used of a type that has been tested to at least ISO/IEC 11801
Category 3.
According to ITU-T the maximum length of flex connecting the bus with terminal equipment may not
exceed 33 feet (10 meters). Some ISDN providers or devices may require a lesser distance, so consult your
suppliers. In accordance with ITU-T the maximum length of the S-bus depends on the delay constant of the
cable. If this is too great, the time sequence of the equipment signals attached to it may be corrupted. The
maximum distance between NT1 and TE is theoretically 656 feet (200 meters), but in practice 492 feet
(150 meters) is the usual maximum.
SmartNode BRI port configured in USR mode and connected to an S-Bus
The SmartNode acts as TE on the S-Bus: usually no other TE are connected on the S-Bus between the NT1
and the SmartNode. The general S-Bus conditions apply, the maximum recommended bus length is 492 feet
(150 meters).
Note
SmartNode BRI interfaces are internally terminated at 100 ohms.
SmartNode BRI port configured in NET mode
The SmartNode acts as NT1. The general S-Bus conditions apply, the maximum recommended bus length is
492 feet (150 meters).
Note
SmartNode BRI interfaces are internally terminated at 100 ohms.
Installing an S-Bus power supply
If your SmartNode 2000 series needs to be equipped with an optional line power module refer to chapter 8,
“Line power module installation”
on page 114 for a more detailed description of this procedure. Check that
the jumper pins are correctly set for your method of using the IC-4BRV-8V interface card (see section
“IC-
4BRV-8V 8-channel gateway interface card for ISDN BRI”
on page 35.
Synchronous serial interface
The SmartNode 2300 supports the V.35 and X.21 standard for synchronous serial interfaces at speeds up to 2
Mbps. Devices that communicate over a serial interface are divided into two classes:
•
Data terminal equipment (DTE): the device at the user end of the user-to-network interface. The DTE
connects to a data network via data DCE, and typically uses clocking signals generated by the DCE.
•
Data communications equipment (DCE): the device at the network end of the user-to-network interface.
The DCE provides a physical connection to the network, forwards traffic, and provides a clocking signal
used to synchronize data transmission between DCE and DTE devices.
The most important difference between these two types of device is that the DCE device supplies the clock sig-
nal that paces the communications on the interface.
Note
A SmartNode 2300 functions as a DTE.
