Cable Modem and MTA Code 122

[Daniel Dias Gonçalves]

I use the Scientific Atlanta DPC2203 Cable modem with MTA . I tried to
use the following configuration and it didn't solve: 

Under your global options
 option voip122 code 122 = string;

under your subnet options
 option voip122 01:04:0a:00:00:02;

Somebody can help me?

Thanks

Daniel