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

Hi,

I have just been trying to run the legacy configuration program and fetch from source fails... well there is a green tick at Claim port, then no further progress.

I have a 32 bit windows 7 PC (kept especially for legacy stuff) the serial port is on the motherboard. 9600 baud, 8 bit, 1 stop, no parity, no flow control.

The cable is a 9 pin null modem and I have done a putty terminal session to another PC.

This makes me think the problem is in the 561.

Any thoughts?

First, check that the COM port is actually COM1, 2, 3, or 4. I seem to recall Meridian.exe can't cope with any others.

Second, try using PuTTY to talk to the 561 and see if you can get any output from it. I seem to recall 561 supports the same serial commands as many other Meridian components for simulating remote key presses etc. If you see responses (there won't be new lines or an echo of what you type if memory serves) or the 561 does what you asked it, then the serial line is working, suggesting a configuration issue at the PC end.

Try reducing the baud rate to 2400.

Neil

Also try rebooting the 561...

Try having the 561 powered but "off". Like power it off with the switch at the back, wait a moment, the flip that switch so that it has power but do not otherwise turn it on (e.g. dont select a source).

Also, OMG you have a serial port on your motherboard?!!

Thanks for the advice. I'll give the low baud rate a go. I think I tried power off, wait, on and don't touch anything but will give that another go.

Puttying to the 561 does not give a response.

Re: Serial port on motherboard... I keep an old PC (windows 7, 32 bit) for just this sort of thing (also have an old citizen dive watch the comms software doesn't like W10x64). Even modern boards (I have an AM4 Ryzen 7 PC too) have a com header on the motherboard, a £2 bracket with a 9-pin d-sub on it fits in the back panel.

I've reset everything/turned off/on/unplugged.

Tried 2400 baud.

When I have a com port monitor running, as soon as I send anything to the 561 (either from putty or MCP) the 561 starts a continuous stream of a mix of xC0 and x80

Any thoughts?

Do you mean bytes 0xc0 and 0x80, or the literal strings "xC0" and "x80"?

On second thoughts, I'm not sure if 561 supports serial control for integration purposes; I thought the port on it was for configuration via Meridian.exe only; if that is the case then the protocol is binary (and with a checksum byte IIRC) and not easily spoken by human.

What do you see if you run the port at 9600? (It can't be the same, but how it is different might be telling.)

I meant the bytes 0xC0 and 0x80

The 561 does support control via serial as well as configuration.

Those values were shown when the port was set to 9600, 8, parity none,1 stop, no flow. I ran a serial port monitor, connected putty to com1, and typed LD.

Similar results are generated with MCP, the program sends F1 (i think) then the 561 responds with a continuous sequence of a mix of those bytes.

So both of these bytes have the high bit set: I seem to recall something about that being the serial protocol used for Meridian.exe and/or for "please replicate Meridian Comms on the serial port", as no serial control commands (source select, volume, etc) have the high bit set. This suggests it might be stuck in some sort of odd mode.

Without access to the specs for Meridian Comms or the Meridian.exe configuration protocol, I don't think we can really interpret what this means: it might be an error code, it might be it being stuck in some other mode.

If a total reset doesn't fix it I imagine this might be some kind of fault, but we'd need somebody with more inside Meridian knowledge to interpret it

I beg to differ: I routinely use Meridian.exe to configure my 561. The manual even has a whole section on it. Are you thinking 562?

The 561 supports both firmware update and remote control via its serial port, I can confirm that I've done both. The latest firmware is 1.77.

If a bit is stuck 'high', then it could either be a problem with the computer's serial port or the serial port in the 561.

I normally connect at 9600,N,8,1 (9600 baud, No parity, 8 bits, 1 stop bit), without any problems from an old laptop with dedicated (i.e. real) serial port. I try to stick clear of USB to Serial converters if possible after having a bad experience with one whilst attempting a firmware upgrade, although they're generally OK for configuration.

I think you need to either try a different computer or another piece of Meridian equipment and see if you can control it using the Meridian Remote Control application. If that works, then configuration should be fine.

Good luck,

Steve