Re: Signaling MIB - Draft 3 - Last Call - pktcSigDevToneT able (Issue4)

There is no need for any additional power objects for each frequency. The original comment submission is based on a misinterpretation of the specification. Here is how it works:

The 300 001 specification states a RANGE of values for the frequency and power (i.e., x1=minimum level, x2=maximum level) that CPE (phones/fax/modems) should be able to accept as input from the various country/operator networks. The range explanation is in the text preceeding the Table 1.7.1 in 300 001. In reading an entry from the table, the frequency may be any value between f1 OR f2 but not both combined. For the power, the level will be in the RANGE that is stated regardless of the actual frequency being used. Thus, the single power level in the MIB is sufficient. This interpretation is further supported by supplement 2 to the ITU-T 181 specification which states: "f1//f2 in some exchanges frequency f1 is used and in others frequency f2 is used." Given the table 1.7.1 example for dial tone for Belgium, the correct interpretation is f1 (420 Hz would probably be 425 Hz +/- tolerance) o
 r f2 (455 Hz would probably be 450 Hz +/- tolerance) at a SINGLE power level within the R!
 ANGE -20 dBm (p1) to -4 dBm (p2).

Again, these are not the source specifications but a statement of the possible operating values that may be supplied to the CPE devices at the end of the local loop.

The implication is that a source (eMTA) that generates a frequency at an amplitude within the stated ranges should be acceptable to CPE devices. 

Gordon Beacham
Digital Core Gateways, BCS
Motorola, Inc.
858-404-2335
[email protected]