We had trouble connecting to a Rapide Lite printer, it's user figured out that the culprit was a auto-reset jumper JP14 on the printer's Melzi2.0 board. It was closed in the original configuration, which means any port connection will require a (manual?) reset. This can be done in Repetier-Host / Printrun with the "Reset on connect" setting?
He pointed us to the following relevant line in Repetier-Host / Printrun:
https://github.com/kliment/Printrun/blob/master/printrun/printcore.py#L200
It seems that the Melzi board requires the reset jumper set in order to upload the firmware (http://reprap.org/wiki/RepRapPro_Huxley_maintenance#Uploading_firmware_to_your_Melzi) It has something to do with the FT232RL USB to UART chip (didn't research further on this). So if the manufacturer left the jumper on, any port connections will require a setDTR to connect.
We had trouble connecting to a Rapide Lite printer, it's user figured out that the culprit was a auto-reset jumper JP14 on the printer's Melzi2.0 board. It was closed in the original configuration, which means any port connection will require a (manual?) reset. This can be done in Repetier-Host / Printrun with the "Reset on connect" setting? He pointed us to the following relevant line in Repetier-Host / Printrun: https://github.com/kliment/Printrun/blob/master/printrun/printcore.py#L200