11.1.1.2 LAPB Address Structure

The address field is only required when LAPB is being used over a Public Switched Telephone Network (PSTN). In this case, the dl_address fields contain the PSTN address, in the format defined by the pstnformat structure:

struct pstnformat {
   uint8   pstn_len;               /* Address length in octets */
   uint8   pstn_add[20];  /* LAPB Address in hexadecimal */
 };

The members of the pstnformat structure are:

The file /usr/include/netx25/sdlpi.h contains the structure definition.