ZyXEL Communications P-971M User Manual

P-971M User’s Guide

Chapter 2 Connection Screen.

28

Modulation

This is the method used to encode transmission information, similar to FM or AM on 

your radio. The P-971M supports QAM256 or QAM64 (Quadrature Amplitude 

Modulation) for the downstream channel. 

Symbol Rate

The symbol rate (in Kilo symbols/second) for communication from the CMTS to the 

P-971M. This is set during initial configuration with a value supplied by the CMTS. 

Typical values for QAM64 are 5.05 Mega-symbols/second, and for QAM256 5.36 

Mega-symbols/second.

Downstream 

Power

The power level (in decibels/mili-volt). This value is set by the CMTS.

Upstream 

Channel

This is the data path used by the P-971M for sending information to your CMTS.

Lock Status

The P-971M is either Locked or Not Locked on to the channel advertised by your 

cable operator’s CMTS.

Channel ID

A standard channel number from the DOCSIS 2.0 specification. Channel numbers 

and channel frequencies are specified in pairs in DOCSIS 2.0.

Upstream 

Frequency

A standard channel frequency (in hertz) from the DOCSIS 2.0 specification.

Modulation

This is the method used to encode transmission information, similar to FM or AM on 

your radio. The P-971M supports QAM16 or QPSK (Quadrature Phase Shift 

Keying) for the upstream channel.

Symbol Rate

The symbol rate (in Kilo-symbols/second) for communication from the P-971M to the 

CMTS. This is set during initial configuration with a value supplied by the CMTS.

Upstream 

Power

The power level (in decibels/mili-volt). This value is set by the CMTS.

CM IP Address

This is the IP address negotiated with your cable operator, after a successful 

download of the modem configuration file and DHCP negotiation (e.g.10.21.0.11). 

This field may also be blanked out with a series of dashed lines (--- --- --- ---) 

indicating that the modem configuration failed or is in progress; no IP address has 

been set.

Duration

The IP address negotiated with your cable operator has a default lifetime of 7 days 

(e.g. D: 00 H: 01 M: 00 S: 00). The sequence (D -- H -- M -- S --) indicates that your 

modem configuration has failed or is in progress; no IP address duration has been 

set.

Expires

This is the expiration date of the IP address, after installation of the modem 

configuration file and DHCP negotiation. The default is 7 days (e.g. Wed Jul 02 

00:26:23 2005). A sequence of dashes (--- --- -- -- -- -- ----) indicates that your 

modem configuration has failed or is in progress; no IP address expiry date has 

been set.

Current System 

Time

This is the current date and time, and is set by your cable operator’s time server.

Table 1   Connection Screen Summary  (continued)