The CyberSURFRTM connects to the subscriber PC using a standard 10BaseT ethernet connection. A single CyberSURFRTM supports communications for multiple personal computers with IP addresses. An ethernet wiring hub interface provides the connections for multiple PC's.
The CyberSURFRTM Cable Modem supports IP communications from the subscriber's PC to host computers and servers. The CyberSURFRTM Cable Modem is not assigned an IP address and does not require an IP subnet. The modem performs the function of filtering and forwarding packets both to and from the PC attached to it, giving the appearance that the PC is directly connected to a LAN in the cable headend.
A RF transmitter and receiver in the CyberSURFRTM Cable Modem provide the physical layer communications over the HFC system. The data from a subscriber PC is transmitted upstream on a 768 kbps shared packet data channel which uses 600 kHz of bandwidth. Downstream the subscriber shares a 30 Mbps channel which uses 6 MHz of bandwidth and provides a maximum of 10 Mbps throughput to each subscriber. Throughput varies depending on internet access, channel load, PC processor and configuration, and headend equipment load. The CyberSURFR TM Cable Modem operates in the upstream spectrum of 6 MHz - 42 MHz and downstream between 65 MHz - 750 MHz.
High performance communications across HFC systems is ensured by the CyberSURFR TM Cable Modem's ability to identify and correct errors caused by transient ingress noise through sophisticated forward error correction (FEC) techniques. In addition, the frequency agility feature embedded in the Cable Router enables the CyberSURFR TM to switch automatically to an alternate frequency if a sustained high noise level is experienced on the existing frequency.
Secure communications is supported through the use of Data Encryption Standard (DES) in both upstream and downstream transmissions. User data is encrypted providing complete privacy to subscriber transmissions over the shared HFC system. When the CyberSURFR TM is powered up, a registration authorization is performed to ensure that a subscriber is using a valid system CyberSURFR TM Cable Modem.
The CyberSURFR TM Cable Modem is easily installed by connecting it to the subscriber PC using a standard 10BaseT Ethernet connection. The installation is completed by simply plugging the CyberSURFR TM Cable Modem into the cable in the home. The CyberSURFR TM Cable Modem will then automatically go through the registration and authentication process. Four LEDs indicate connectivity status and also act as a diagnostic aid. The TCP/IP address for the subscriber's network device is either configured statically in the IP communications software or the address can be configured dynamically by using a DHCP server.
Management of the CyberSURFR TM Cable Modem is provided through an SNMP proxy agent in the Cable Router and the Enterprise MIB variables. MIB II variables are also supported. Software in the CyberSURFR TM Cable Modem can be updated to the latest version through a down-line load process executed by the Cable Router to allow an operator to maintain consistent software throughout the subscriber base.
A customized label can be affixed on the inset on the crest of the wave of the front panel for brand labeling of the CyberSURFR TM Cable Modem.
Transmitter
Bandwidth: 600 kHz
Data Signaling Rate: 768 kbps
Symbol Rate: 384 ksym/sec
Modulation: pi/4-DQPSK
Transmit Frequency Range: 6 MHz - 42 MHz w/dynamic frequency agility
Input Impedance: 75 Ohms (nominally)
Dynamic Range: 24 to 55 dBmV
Receiver
Bandwidth: 6 MHz
Data Signaling Rate: 30 Mbps
Symbol Rate: 5 Msym/sec
Modulation: 64 QAM
Receive Frequency Range: 65 - 750 MHz w/frequency selectable
Channel Plans: Standard, IRC, HRC
Input Impedance: 75 Ohms (nominally)
Minimum CNR (at receiver): 30 dB
Dynamic Range: +5 to -15 dBmV
Group Delay Tolerance: 130 nS
Rear Panel Connectors/Controls:
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