Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems 561 Serial Port Problem

I thought about this too, but I don't think it is likely to be either port: RS232 is a serial protocol, only one wire is used for sending all the bits in a byte (unlike, say, a parallel printer port which has an array of eight), so it can't be the wire or port that is routinely corrupting only one in eight bits. I'm assuming that inside the 561 the Z8 microcontroller's internal UART is used so it will be memory-mapped byte-wise and then transmitted a bit at a time. Also it doesn't explain why the continuous stream of these bytes when only three (LP\n) were sent.

It is most certainly worth checking with another PC or another component to see where the oddness follows though: it might be another process using the port for something else on the PC or the 561 at fault.

As for USB serial adaptors, I only ever buy them direct from FTDI - not cheap but you know it's not going to be a cheaply built dodgy clone.

Apologies, senior moment, post deleted. 20 years on, I had forgotten the differences in the capabilities of 561 and 565, the latter definitely didn't do firmware or configuration via serial, even in Z3 guise.

Having tried 3 computers (2 USB serial, one motherboard serial), 2 serial cables, run putty on two machines, tried different baud rates, UART FIFO off, 1, 7 and max (14).

I am going to have to accept that there is something internally wrong, but since everything else works and it is only source labeling that I wanted to change I will stick with it as it is.

Thanks for everyone's helpful advice.

I would like to share my way of connecting to our Meridian 500 series products.

I bought some Ugreen RS232 Female plugs using AliExpress, and hoocked them to a Apple MacMini permanent.

The MacMini is running a Windows XP Virtual machine, using VMware Fusion and the cables are permanently pass through to that virtual XP machine running the Meridian legacy configuration software.

This cable worked fine so far, also for our DSP33 speakers.
I can highly recommend it.

Using a PC with a virtual machine, with tools like free software Vmware player you could achieve the same result.

The cable I am using is a Ugreen USB RS232 Com Port. Make sure you buy the RS232 Female version of course.

I hope this info is usefull.

I have connected all of our Meridian products, permantly to our MacMini, and the MacMini is only needed for configuration nothing else in our setup.