The service database provides a way to associate arbitrary human-readable strings with the parameters needed to uniquely identify a particular protocol service. The strings are passed to lgo_Open() and lgo_Attach() to identify the service.
The default service database is service.db located in the cfg directory. This is a text file which can be edited with any text editor, such as the Windows editor notepad.
Each line in the service database has the following format:
<service> <protocol> <major device> <minor device> <cfg file>
The # character in the first column is the comment marker. Comments and blank lines are ignored.
The service names in the default database have the form:
# # X.21 bis # PHYS0 4 0 0 null.cfg PHYS1 4 1 0 null.cfg PHYS2 4 2 0 null.cfg PHYS3 4 3 0 null.cfg # # HDLC LAPB # LAPB0 5 0 0 null.cfg LAPB1 5 1 0 null.cfg LAPB2 5 2 0 null.cfg LAPB3 5 3 0 null.cfg # # X.25 Major Device with SVCs and 8 PVCs # PKT0 6 0 0 null.cfg PVC01 7 0 1 null.cfg PVC02 7 0 2 null.cfg PVC03 7 0 3 null.cfg PVC04 7 0 4 null.cfg PVC05 7 0 5 null.cfg PVC06 7 0 6 null.cfg PVC07 7 0 7 null.cfg PVC08 7 0 8 null.cfg
However, any strings can be used. For instance, for a connection to Dallas on physical line 0, you might name X.21 bis, HDLC LAPB and X.25 major device services DALLAS_X21, DALLAS_LAPB and DALLAS_X25. X.25 PVCs on that line might be designated DALLAS_1, DALLAS_2, etc. If the connection to Dallas later changes to line 3, only the service definitions need to be changed.
A single service definition may have multiple names. For instance, if physical line 0 is sometimes used for a connection to Dallas, sometimes for a connection to Paris, PARIS_X21, PARIS_LAPB and PARIS_X25 might be defined in the same way as DALLAS_X21, DALLAS_LAPB and DALLAS_X25. In this case, the connection to Paris could not be opened at the same time as the connection to Dallas.
Note: Use of the service database is optional (but recommended). The parameters associated with the service name can be passed directly as parameters to lgo_OpenProtocol() and lgo_AttachProtocol().