# Using sub-addressing

NaturalFax supports the sub-addressing feature for sending and receiving. By default, sub-addressing is enabled on the receive side and disabled on the sending side. To enable the sub-addressing feature, set useSUBADD to NFX_YES in NFX_TRANSMIT_PARMS or NFX_RECEIVE_PARMS.

In NaturalFax demonstration programs, nfxsend uses -a subaddress to enable or disable the sub-addressing feature. If -a subaddress is used by nfxsend, a transmitter sends sub-address information to the receiver depending on the receiver's capability. If the receiver does not support this feature, the user is notified that sub-address information was not sent, but that the fax was sent.

The following example shows sub-addressing enabled:

nfxsend -plps0 -d555 -s0:0 -a 12549 -v sample.tif
nfxrecv -plps0 -s0:2 -v receive.tif

The following example shows sub-addressing disabled:

nfxsend -plps0 -d5555 -s0:0 -v sample.tif