[arm-allstar] COR timer -- was: COR question

Wed Dec 16 22:33:07 EST 2015

Jon,

 You are absolutely right. The active low state is far safer but unfortunately it seems as many radios have active high as active low. The important thing is to be aware it could happen. You don't need to be paranoid about it just aware.

We have pondered a timer for longer than you can imagine. Dave and I have talked about methods and possible outcomes over and over. If a timer had been in the code from day one we probably would not  even be considering this a problem worth talking about at this point. Fixing the problem at the source is the easiest way to do it but that only fixes it for those that have updated their code to include the timer. There will be many out there that either never update or that will be using a variation of the code that does not pick up the timer update. I still think it is a good addition and at least will give the user the piece of mind that his system is not going to tie up a circuit for an extended period.
73 Doug
WA3DSP
http://www.crompton.com/hamradio

> Date: Wed, 16 Dec 2015 21:11:20 -0500
> From: jrorke at cogeco.ca
> To: arm-allstar at hamvoip.org
> Subject: Re: [arm-allstar] COR timer -- was: COR question
> 
> I believe the chip in the FOBS and the URI were designed to have the 
> inputs pull hi internally and looks for a hi to lo transition to take 
> action.
> 
> I dont want to spark the debate over weather active low vs active hi cor 
> is better. The real answer is it shouldn't matter as long as you take 
> into account what your connected radio does in all modes of operation.
> 
> Some radios only give a voltage change but dont pull to ground, some 
> give an active lo, some have an open collector that either pulls to 
> ground on signal or stays low and floats hi with signal.
> 
> In the case of active low (USBinvert) it should work most of the time, 
> but as it has been said, in some radios the COR line goes low when the 
> radio is turned off.
> I have even seen some radios where the COR ling goes active on transmit too!
> 
> So if you switch to active hi (USB) then it should also work, and if the 
> line goes low when the radio is turned off, then it shouldn't cause a 
> problem. But if you disconnect your radio from the URI/FOB then it will 
> think you radio is receiving and you are back to square 1.
> 
> Adding a timer may help but in my opinion it just masking the problem 
> and it should be delt with in the radio.
> 
> I personally use USB invert (Active low) on all radios connected to 
> repeater controllers and/or URIs.
> 
> I check the output signals on all the radios I intend to use and if I'm 
> not satisfied that I can use an active low output then I modifiy the 
> radio using an NPN transistor to give me and active lo open collector.
> 
> This way the COR line connected to the URI/FOB will always see an active 
> lo COR or PL signal and the radio will never source any voltage whether 
> its on or off or disconnected.
> 
> If you cant add the circuit and the radio does some unpredictable things 
> with power glitches, then perhaps add  battery back up to the radio so 
> it doesn't reset on power bumps and stays at its normal mode.
> 
> My point here is to ensure you investigate your radio and take the 
> necessary precautions so that your node doesn't go into transmit mode 
> for no reason.
> Unfortunately this is a danger when setting up simplex nodes. If you 
> node thinks its receiving a signal from your radio it will TX over the 
> net to any connected nodes and cause them to TX and one may not know 
> this is occurring.
> 
> just my 2 cents  worth. YMMV
> 
> Jon VA3RQ
> 
> 
> 
> 
> 
> 
> 
> On 12/16/2015 5:28 PM, David McGough wrote:
> > Hi Guys,
> >
> > I'm not making promises, but, I'll take a look at adding an adjustable COR
> > timer, functioning very much like the current "totime=xxx" for the TX
> > timeout.
> >
> > I know this would be a VERY useful feature!
> >
> > 73, David KB4FXC
> >
> >
> > On Wed, 16 Dec 2015, Doug Crompton wrote:
> >
> >> Yes, it definitely would be adjustable.
> >> 73 Doug
> >> WA3DSP
> >> http://www.crompton.com/hamradio
> >>
> >>
> >> From: ka5iid at swbell.net
> >> Date: Wed, 16 Dec 2015 09:10:32 -0600
> >> To: arm-allstar at hamvoip.org
> >> Subject: Re: [arm-allstar] COR question
> >>
> >> Doug, if a timer is implemented please make it adjustable.
> >> My guess is it would be specified as a receive active timer on the node. It would be reset every time the input toggled.
> >> Stan
> >>
> >> Sent from my iPhone
> >> On Dec 16, 2015, at 8:38 AM, Doug Crompton<doug at crompton.com>  wrote:
> >>
> >>
> >
> > Jim,
> >>   The default is "usbinvert" only because it is configured for the Alinco, tyt etc. radios which go COS low on signal. If you have a radio that goes high on signal and you set it to "usb" you do have to be careful that you do not turn off or disconnect the radio. The CM108 has a pullup so it would put Allstar in an RXKEY condition and lockup a channel if you were connected anywhere. So the warning is to never turnoff or disconnect a radio especially in a connected state.
> >>
> >> This is a warning I always give new Allstar users. We are looking into a SW timer to lessen the issue whether it is intentional or unintentional.
> >> 73 Doug
> >> WA3DSP
> >> http://www.crompton.com/hamradio
> >>
> >>
> >> Date: Wed, 16 Dec 2015 03:02:17 -1000
> >> From: jim.pilgram at gmail.com
> >> To: arm-allstar at hamvoip.org
> >> Subject: [arm-allstar] COR question
> >>
> >>    I'm wondering if there's a specific reason why negative on the COR was chosen rather than positive.
> >> The reason ýI ask is we have had problems with node radios being turned off or power supplies tripping and timing out the system.
> >> We are running mostly Motorola CDM750, 1250 and 1550's as simplex nodes and some repeaters. Most nodes are RPI2 or BBB'S
> >> Can anyone she any light on this?
> >> Jim NH6HI
> >>
> >>
> >> Sent from my BlackBerry 10 smartphone on the Verizon Wireless 4G LTE network.
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