Disabling DSC

When a DSC call is received by our Icom 604, the alert is around 120 decibels and basically makes you snort coffee out your nose if you happen to be taking a sip when the siren goes off. According to the manual, this alarm is supposed to go off after a minute or two, but doesn't. We left the VHF on once, locked the boat and when we returned the fire department had been called because people thought such a hallacious noise must mean the boat was on fire. I thought this lunacy was just a feature(?) of the Icom, but sitting at the dock in Vancouver a vessel docking right behind us received a DSC alert on their Raymarine and it was almost as loud so this appears to be built into the system.

Since this results in our frequently cruising with the VHF off to avoid heart attacks or hearing loss it somewhat defeats the safety purpose of the distress calling. So my question is whether anything can be done? Like cut a diode, or drive a 16 penny nail through the right spot on the PCB, or what?

Any suggestions from anyone?

I'll make a suggestion - Call Icom and ask them what to do.

WesK said:

I'll make a suggestion - Call Icom and ask them what to do.

Click to expand...

Done that. They have no suggestions on how to disable a federally mandated function. When asked why their manual said the alarm would turn off after a few minutes but doesn't, their response was "really?" Very helpful.

We have Icom 604s, and when the DSC alert has gone off (yep, coffee snort) I've punched some buttons and the noise stopped. Can't remember what I've pushed, though. One of the DSC "accept" functions or something like that, maybe...

-Chris

Delfin said:

Done that. They have no suggestions on how to disable a federally mandated function. When asked why their manual said the alarm would turn off after a few minutes but doesn't, their response was "really?" Very helpful.

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If you had mentioned that in your original post, I wouldn't have bothered you with my suggestion.

Much better to assume every poster is unable to figure out that a call to a manufactirer could possibly answer the question.

I know it to be true, but sometimes a quick post on TF will answer the question than the 20 minute hold to the manufacturer.

Thats why I love forums and dislike those that always have the "pat" answer, "call the manufacturer/ subject matter pro."

I wonder if the DSC has a proximity component? If you removed the GPS signal, would it still sound the alarm?

Ted

I haven't had a DSC call in the eight years I've owned my boat and radio so I haven't had that problem.

I wonder if other owners of the same radio have the same problem and what they are doing about it?

Now here's the question (and I assume you won't know the answer yourself): Does the alarm use the same speaker that's used for the radio's audio or does it use a separate "buzzer" type transducer? If it's a separate transducer for the alarm, it would be pretty simple to disconnect it or install a series resistor to reduce the volume.

You would probably want to take it to a pro to have this dome to make sure nothing else is effected.

ranger42c said:

We have Icom 604s, and when the DSC alert has gone off (yep, coffee snort) I've punched some buttons and the noise stopped. Can't remember what I've pushed, though. One of the DSC "accept" functions or something like that, maybe...

-Chris

Click to expand...

Yes, punching any button does silence the alarm. The problem is the alarm. It would have been SO SIMPLE for them to allow this to be something where the volume could be adjusted. Instead, they assume that you are 500 yards away and need to be able to hear it because you are attending a Black Sabbath concert. Insane.

What bothers me is that this is an important safety feature, and my only defense against bleeding ear drums is turning the VHF off. So, if I could disable the unit's ability to process the DSC signal, that is fine with me.

O C Diver said:

I wonder if the DSC has a proximity component? If you removed the GPS signal, would it still sound the alarm?

Ted

Click to expand...

Not sure about every new radio, but up until a few years ago they all sounded the alarm whether registered or hooked up to gps.

In the small commercial operation world...none of that was important and it drove me nuts.

The DSC alarm will definitely get your attention. I've had a number of them go off, startles the bejeezus out of you, particularly if you're focusing on traffic or navigating a tricky spot- I don't know how to shut mine off, and worse, I have 2 VHF's on the bridge, and they're different models. If one sets to screamin', they both participate.

DSC has gotta be the most never-used technology on the boat. I'm a self-professed geek, a button junkie, if you will. I have NO IDEA how to make DSC work, and when I tried to go through the manual, it just made my head hurt. Of course the ops for the different radios are completely different as well. So when the alarm starts to scream, I make a mad dash for the OFF button!!

If you travel a lot with a buddy boat, dsc is a good tool to learn to use, otherwise it is just a great rescue option.

O C Diver said:

I wonder if the DSC has a proximity component? If you removed the GPS signal, would it still sound the alarm?

Ted

Click to expand...

That's an interesting thought. The unit does display lat/long, which I hardly need. I've disconnected the VHF from the GPS and it will be interesting to see if that does the trick.

Brilliant, OC.

Delfin said:

When a DSC call is received by our Icom 604, the alert is around 120 decibels and basically makes you snort coffee out your nose if you happen to be taking a sip when the siren goes off.

Click to expand...

I ripped a stitch laughing over that one.

WesK said:

I haven't had a DSC call in the eight years I've owned my boat and radio so I haven't had that problem.

I wonder if other owners of the same radio have the same problem and what they are doing about it?

Now here's the question (and I assume you won't know the answer yourself): Does the alarm use the same speaker that's used for the radio's audio or does it use a separate "buzzer" type transducer? If it's a separate transducer for the alarm, it would be pretty simple to disconnect it or install a series resistor to reduce the volume.

You would probably want to take it to a pro to have this dome to make sure nothing else is effected.

Click to expand...

Well, you may be fortunate in that yours apparently doesn't work. We received three of them 2 days ago, and one yesterday. As others have noted, this function is not doing what it is designed to do and no one seems to be able to figure out to make it work appropriately, although all seem to agree it is a colossal PITA.

I'll be interested to see if disconnecting the GPS per OC's suggestion works and I'll let you know if it does. Hope so, but as Mr. Sneed suggests, it may not.

Well DSC isn't supposed to be used often.... Ever notice the tab that covers the button says "distress"?

They have classes that teach you about it if you want to shell out the money.

psneeld said:

Much better to assume every poster is unable to figure out that a call to a manufactirer could possibly answer the question.

I know it to be true, but sometimes a quick post on TF will answer the question than the 20 minute hold to the manufacturer.

Thats why I love forums and dislike those that always have the "pat" answer, "call the manufacturer/ subject matter pro."

Click to expand...

I suspect Icom probably could answer the question, but won't. I talked with an Icom distributor who also appeared clueless, but he seemed to suggest that the DSC alarm is just a broadcast message like any other. I doubt that, since the signal overrides whatever volume setting you have for regular traffic and punches it up to nose bleed level, plus cancels the alert when you lunge for any button so you can make it stop. So there must be some separate circuitry involved to process this special signal.

SaltyDawg86 said:

Well DSC isn't supposed to be used often.... Ever notice the tab that covers the button says "distress"?

They have classes that teach you about it if you want to shell out the money.

Click to expand...

I'm suspecting that the 12 year olds who push open that little tab and punch that little button to see what happens may not have taken the course.

DSC is much broader of a feature than the distress button
..it is supposed to enhance tbe concept of radio telephone.

And yes the distress alarm might be different from routine DSC calls, if you were broadcasting a MAYDAY, wouldn't you wan it to be more noticeable?

Could it be this simple ....( link to online manual: file:///C:/Users/Greg/Downloads/M604A_Instruct.pdf)

See, sometimes the Forum works depite a few members negative thinking.

While DSC alerts havent bugged me, WX alerts have and simply learning how to disable or silence it was a simple trip to the manual or forum.

As noted above, perhaps my radio doesn't work as I have never had a DSC alarm go off in all the years I've owned a radio with that feature. No I don't know how to use it except to rip the cover off and push the damn button. Then I'm off to one if the EPIRBs.

Delfin,

After reading my M506 manual, removing the GPS signal may only help you with "Geographic area calls".

Did find something that may help. There is an "Alarm Status Menu". You enter it from the "DSC Settings Menu". One of the options that is selectable is "Discrete". That may tone down the level of the alarm.

Also there is a "Channel 70 Squelch Level" adjustment. The manual is unclear, but my assumption is that the DSC transmits and is received over channel 70. I wonder if you turn the squelch from 3 (default) to 11 (maximum), that might reduce or eliminate all but the closest calls.

Ted

"Auto self terminate" is also selectable under the "Alarm Status Menu".

Ted

Even radios have gotten complicated to the point you need an engineering degree to operate these common items. I long for the day of the old AM radio (double side band) that had a great range. I could talk from Miami four miles off shore to the Berry Islands.

First time it happened to me I was docking at night. In a full enclosure it is way too loud. The only thing I found to make it stop was turning the power off. So I called ICOM to ask how to turn down the volume. "Why would you want to do that?" That was 2003. Still no low-med-hi settings on new radios.

Benthic2 said:

Could it be this simple ....( link to online manual: file:///C:/Users/Greg/Downloads/M604A_Instruct.pdf)

Click to expand...

It is certainly that simple. An ear shattering blast of sound emits from the radio; startled, you leap up spilling your tea and hit your noggin on the overhead; half dazed you lunge for the radio to a.) switch it off, b.) hit channel 16 so that the sound drops from 120 db to around 60 db, c). hit any other button to silence the alarm. The problem is not turning it off, it is the occurrence in the first instance that is the problem. And that only because the cretins who designed this system thought it important for you to be able to hear the alarm from 1/2 mile away even if you happen to be six feet away.

High Wire said:

First time it happened to me I was docking at night. In a full enclosure it is way too loud. The only thing I found to make it stop was turning the power off. So I called ICOM to ask how to turn down the volume. "Why would you want to do that?" That was 2003. Still no low-med-hi settings on new radios.

Click to expand...

You must have spoken to the same tech I did. He also seemed perplexed why anyone would want to turn off such a valuable alert system to the presence of idle teenagers in nearby boats with nothing better to do than push the little red button.

psneeld said:

See, sometimes the Forum works depite a few members negative thinking.

While DSC alerts havent bugged me, WX alerts have and simply learning how to disable or silence it was a simple trip to the manual or forum.

Click to expand...

Be nice if that were the case, but it's not. The Icom manual devotes 30% of its pages to DSC operation with nary a word on how to disable or diminish the alarm, because that capability doesn't exist. My guess is that the Coast Guard, who is responsible for this cluster thought it inappropriate to allow users any control over how their radios function.

The other functions for DSC you mentioned with regard to messaging between vessels do exist, but are a solution in search of a problem. In exchange for pressing about 10 buttons I can avoid picking up the receiver and hailing another vessel? In the history of boating, how many have ever used this capability? Just curious, but have you? Incidentally, if you want to see how simple it is to replace the cumbersome process of hailing another vessel with the microphone with a simple 10 step process of pressing buttons, Icom has this video to show you how to do it:

Know what. I'm now very glad my simple, self-installed and cheap, Si-Tex VHF, that always works perfectly and never makes me snort coffee, does not have DSC. For ages I regretted not having it - just in case, sort of. Have we ever needed it...NO. I feel better now. Much better.