{
{   The purpose of this request is to establish access to a specific
{ channelnet service access point.  Channelnet datagrams may be sent and
{ received over the opened service access point.  The opened service access
{ point may be used only by the task which issued the open request.
{
{       NAP$CN_OPEN_SAP (SAP, MAXIMUM_DATA_LENGTH, STATUS)
{
{ SAP: (input) This parameter specifies the service access point which is to
{       be opened.
{
{ MAXIMUM_DATA_LENGTH: (output) This parameter specifies the maximum length of
{       the data which may be sent over the opened service access point in a
{       single datagram.
{
{ STATUS: (output) This parameter specifies the request status.
{       CONDITIONS: nae$layer_access_not_authorized, nae$sap_already_open
{       IDENTIFIER: 'NA'
{
