S7 200 Comms trouble

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Hello, I recently bought a brand new RS232/PPI Multi-Master cable (6ES7 901-3CB30-0XA0) so that I can play with an S7 200 CPU 226 that I have. Everything was going ok for the first few hours of 'playing' but now I lose comms frequently and recieve various error messages: "THE PPI MULTI-MASTER CABLE WAS DISCONNECTED FROM THE PROFIBUS NETWORK. ANY PREVIOUSLY ESTABLISHED CONNECTION HAS BEEN LOST." I'm not even on a profibus network. "YOU MUST USE THE (RS232/USB) PPI MULTIMASTER CABLE TO COMMUNICATE ON A MULTIMASTER OR ADVANCED PPI NETWORK". This appears sometime when I first try to go online - seems to suggest to me that Step7 Microwin V4 cant actually see the PPI lead. "A CHARACTER-BUFFER OVERRUN HAS OCCURED. THE NEXT CHARACTER IS LOST." "NO CONNECTION TO THE SPECIFIED ADDRESS COULD BE ESTABLISHED. POSSIBLY AN INVALID OR NON EXISTENT ADDRESS." Usually the PPI led on the lead stays on but the Tx and Rx leds extinguish when I get these errors. I've checked my comms settings and they are as per the manual. Unfortunately I have only one PLC and one lead so I cant try other hardware. Any suggestions? PLC or Lead fault? UPDATE\EDIT: I've resolved this. Edited by gruntstripe

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How did you resolve te problem with "A character-buffer overrun has occurred. The next character is lost."?

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