You can use the command pstnport attribute set reverse-pole-pulse reverse-pole-pulse-value to configure the charging of a pots user. The charging mode can be KC charging or polarity-reversing pulse charging.  When the MSAN interworks with the core network, the MSAN controls whether to issue KC or support the polarity-reversing pulse.

1.   When you set the parameter reverse-pole-pulsereverse-pole-pulse-value to disable, the polarity-reversing pulse is disabled, and the KC charging is used.

2.     When you set the parameter reverse-pole-pulsereverse-pole-pulse-value to enable, the polarity-reversing pulse is enabled, and the Pulse-based charging is used.

3.   When the Phone is a Public telephone, it should be KC charging.

Useful info, thanks .