Via Systems Technical Support

Via Systems

Technical Bulletin

Summary: DDE links fail to update or the connection seems to hang.

ViaDuct All

Symptom:

Communications between Via Duct and the host system seem unresponsive, notably during DDE transfers.

Problem:

The Via Duct "transmit rate" parameter may be set too low.

Solution:

The "transmit rate" parameter (found under the Via Duct menu SETUP:COMMUNICATIONS) controls how many "characters per second" are sent to the host system. It is designed to prevent "overflow" of data on the host system by slowing down transmissions between the PC and the host. Many modern data base systems (i.e. UniVision, UniData, UniVerse) do not suffer from data loss during fast bursts of communications; on these systems, the transmit rate can be set much higher than the default (50 cps). In order to improve performance, especially during DDE, but possibly during other forms of data communications, set the transmit rate as high as possible. Setting the parameter to "0" instructs Via Duct to send data continuously; if your host system can support this rate, performance may improve significantly. Conversely, if you are experiencing data loss during DDE transfers, decrease the "transmit rate" parameter until all data is correctly received by your host.