This structure indicates valid and invalid PNSTATION elements.
typedef struct tagPNAVSTATION{
DWORD dwStructureSize;
DWORD dwAv1;
DWORD dwPNReserved;
} PNAVSTATION;
| Flag | Bit | Description | 
| PN_ASN_NUMAVAILABLE | 0 | Unsupported | 
| PN_ASN_NUMUSED | 1 | Number stations used is valid or invalid. | 
| Reserved for future use | 2-31 |