Printer Mode

The TN3270 protocol supports both SCS (LU1) and 3270DS (LU3) printer sessions. When a client connects and requests a printer session, the type of printer is negotiated by the client and server. Most CICS applications that send output to a printer expect a specific type of printer (either SCS or 3270DS), so you must ensure your printer client connects as the correct type.

There are two main versions of TN3270: the original protocol, sometimes called "Classic TN3270", and "TN3270E" (for Enhanced). SCS printing is only supported with TN3270E. Most client software supports TN3270E but can often be configured to use Classic TN3270. If your client is using Classic TN3270, it will always be a 3270DS printer.

With TN3270E, a printer client session can request to be a 3270DS (also called LU3) printer or an SCS (also called LU1) printer, or both. Supporting both types of printing to a single client requires mainframe capabilities that Enterprise Server for .NET CICS does not currently support. If a printer client requests both types of printing, CICS will look for a TypeTerm resource definition for the requested terminal LU name. If the client doesn't request an LU name, or the requested device does not have an associated TypeTerm, or that TypeTerm's Device property does not specify "SCSPRINT" or "3790", then the printer type will be 3270DS.

To use SCS, a printer client session can either:

• Request only SCS printing support (and not 3270DS printing). Consult the documentation for your TN3270 client software.
• Request an LU name that is associated with an appropriate TypeTerm:
  • The LU name sent by the client (configured in your TN3270 client software) matches a Terminal resource in the installed CICS resource definitions for the region.
  • The Terminal resource has a TypeTerm property that names a TypeTerm resource that is also installed in the region.
  • The Device property of that TypeTerm has the value or . (These two values are equivalent in Enterprise Server for .NET.)