DIAdem provides you with tools to connect to databases using SQL. Specifically, you can use SQL_Connect to open a connection to a database through a DSN (Data Source Name). The DSN has to be configured on the local machine (Control Panel -> Administrative Tools - > Data Sources) and has to point to the remote Database. You can map a network drive in the local machine so you can browse to your remote Database. The DSN will provide the link between DIAdem and the remote Database.
If your communication has to be throught telnet, then I suggest you try to use an ActiveX control. VBScript doesn't support Telnet natively, but it does support ActiveX controls. You can create one from Visual Basic or try to find a telnet client that has one already.