Technical support memos


April 22, 2008
Remapping LPT ports
Adv 5.1 (DOS mode) and prior; TAS 5.1 (DOS mode) and prior
Addsum staff (Copyright 2008 Addsum Business Software, Inc.)

Users of 16-bit character based systems that output via a mapped LPT port (which can include physical output to a USB connected printer) typically must map or NET USE to an LPT port in order to be able to print from these "DOS" programs. The way to do this is described in Microsoft knowledgebase articles 314499 relating to XP and 154498 for 2000/NT. (See How to print to a network printer from an MS-DOS-based program in Windows XP and How to Print to [a] Network Printer from MS-DOS-Based Programs.)

With Windows XP, a non-administrative user cannot map to an LPT port if that port actually exists on the local printer (attempts to do so will result in an "access denied" message). To avoid having to provide a user with full admin privileges on a local PC, the simplest solution is to instead map to a non-physical port such as LPT2 or LPT3. This is somewhat more be problematic with versions of Advanced Accounting and TAS prior to 4.0 which only supported LPT1 (however there is a solution). Since LPT2 and LPT3 is supported for subsequent releases, the easiest solution then is to NET USE to a non-existent LPT2 or LPT3 port and then provide the user with a printer option linked to port 2 or port 3 (in Advanced Accounting 5.1 this would be done via Y-System Maintenance and then H-Multi Printer Setup). For further discussion of this solution and one for users that only have LPT1 as an option (such as TAS 3.0 and Advanced Accounting 3.0), see Microsoft Knowledgebase article 313644 entitled Non-administrators cannot remap an LPT port to a network printer.

Note that to avoid a printing delay to a network printer, DOS users may also need to make the WOW LPT_timeout change that is discussed in a prior Addsum tech support memo entitled Speeding up network printing in the DOS mode.

In addition to TP5WIN.EXE (5.1 Windows 16-bit mode), TP6RUNTIME.EXE (TAS 6 versions, 32-bit) and TP7RUNTIME.EXE (TAS 7 and 7i versions, 32-bit) are not at issue because they do not print via mapped LPT ports.

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