Radio Frequency (RF) Information

Enter the following information to describe the modem downstream frequency, upstream channel ID, and network access.

Downstream Frequency

Specifies the center frequency (in multiples of 62500 Hz) for the downstream channel to be used by the modem. (Typically, this parameter is not specified in the configuration file because the modem automatically scans the downstream for available frequencies.)

This frequency is used as the receive frequency by the modem. This frequency is an override for the channel selected during scanning.

Example: 453000000 (Hz)

This example indicates the typical search frequency of the Cisco modem. With a specific downstream frequency included, the modem is likely to be more reliable and recover faster should there be a network fault.

Note: To change the frequency allocation of your network, you need to change the downstream frequency value, potentially up to one week in advance of this frequency allocation change. The advanced time required is dependent on your DHCP lease time. You also need to change the file name in order for the modem to accept it as a new file.

Upstream Channel ID

Specifies channel ID for the upstream channel to be used by the modem. (Typically, this parameter is not specified in the configuration file but set dynamically by the CMTS during provisioning.)

The modem MUST use the upstream channel ID. The modem listens to the defined downstream channel until an upstream channel description message with the upstream channel ID is found. The upstream channel ID is an override for the channel selected during initialization.

If you are using a 2-way RFI modem, the default value is the current upstream channel.

If you are using a telco return modem, the value MUST be set to 0.

If you are using a Cisco modem, this field should be left blank---DO NOT set.

Network Access

This mandatory field determines whether CPE devices attached to the modem are allowed access to the network. The default is to allow access for CPE devices.

• If the value entered is "1" the modem is allowed access to the network

• If the value entered is "0" the modem is denied access to the network

Note: Network Access is used so that when the installer plugs a modem in, it can be accessed remotely by the service provider, but is nonfunctional to the subscriber. The modem can be configured (locally or remotely) and then brought online. Network Access turns the modem on and off for the subscriber. It DOES NOT disconnect the modem from the network. It only disconnects the modem from the CPE network.

Related Topics

Overview: Cisco DOCSIS CPE Configurator