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Author Topic: Help - Portable Emergency Autopatch  (Read 5531 times)
VK5CQ
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Posts: 123




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« on: January 11, 2009, 03:39:02 AM »

SUMMARY:

In Australia's Outback (or anywhere else that's) hundreds of miles (or KM's) from the nearest town or medical facilities, we hams could provide valuable assistace in medical emergencies or larger disasters (hours before well-equipped emergency services can arrive on-scene), if we carried a "Portable Autopatch" & a handheld radio, as well as our VHF/UHF mobile radio in our vehicles, while travelling or working in the Outback.


SITUATIONS:

1. A car crash in Outback Australia... of 5 people in the car, 4 are injured, including the driver with head & leg trauma...

The crash occured about 200 km's from the nearest town, and NO ambulance or police stations or hospitals are nearer...

The nearest clinic - staffed with a Remote Area Nurse from time to time - is NOT staffed at the time (1 Jan 2009, about 3 AM)...

The nearest homes are those of an Aboriginal community just up the road... FEW have telephones, some have NO electricity...

The head trauma patient - who also has back pain - is take to a house with NO PHONE or 2-way radio...

That house is FAR out of range of any cordless phone, & there's NO CELL-PHONE COVERAGE here in the Outback...

NO satellite phone is available at the time...

2. The community is located near a railway that's used daily (by both freight & passenger trains), but there is NO RADIO COMMS between the two.

There's been a derailment incident in the same area, ie, just a few years ago.

So, there's a well-documented & regular need for communications here.

3. Australia's well-known Royal Flying Doctor Service (RFDS) has on-call duty doctors, who can be consulted by phone via a free-call phone number...

but with NO phone service at patient's bedside, it was NOT possible to speak with the RFDS doctor while examining the patient...

Instead one examined, then drove to the phone, transmitted examination results, got orders from the doctor, & drove back to the patient... not at all satisfactory.

4. English skills of the available Aboriginal residents - during this incident - were NOT such that the person examining the patient could simply hand a radio to a resident (ie, at a location with a working telephone) and ask them to relay messages to doctor or hospital.

Holding such a radio radio near the phone & switching  between mic and speaker (while also coordinating use of the radio's Push-to-Talk button) would NOT be optimal, to say the least.

5. A licensed Radio Amateur lives nearby, is happy to assist, ie, in an emergency, do what needs to be done; in the longer term, help people get Ham tickets, etc. so there'll be more communications options next time.

PROBLEM:

We need a way to have even -temporary- bedside access to a telephone (available within 3 km of the patient, in this incident) for consultation with the doctor.

ONE SOLUTION:

If we hams carried a "Portable Autopatch" (ie, a simple interface between the modern, Off-the-Shelf VHF or UHF radio(s), that we have in vehicles, it would be easy to:

1. park the cooperating Ham's radio-equipped vehicle near a home or business, whose resident or operator is prepared to loan a phone line for the consultation (several would have been willing to do so, in this incident)

2. plug-in the (proposed) "Portable Autopatch" between the phone line (via an phone-extension cord, that the Ham would likely need to carry) and the Ham's mobile VHF or UHF radio

3. at the patient's bedside, use a handheld radio to call the RFDS doctor (remember, it's a free call, so there'd be NO calling costs to the cooperative resident or business operator)

4. after the consultations are complete, the Ham would remove & pack away the Portable Autopatch and the phone-extention cord & continue on his or her way...

Now, all we need is such a Portable Autopatch...

What's available?

...either new or used - preferably, in an Off the Shelf product?

(I'd guess that companies such as MFJ should have or be interested in creating a cost-effective product.)

A reliable home-brew product would also be fine.

Any leads would be welcome... TIA & 73,

Chuck - VK5CQ

eMail: Chuck.VK5CQ@gMail.com

sMail: VK5CQ
       GPO Box 222
       Adelaide 5001
       AUSTRALIA
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KG4RUL
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« Reply #1 on: January 11, 2009, 05:31:34 AM »

Have you looked at repeater controllers?  IF you can get a Carrier Operated Relay (COR) output from your vehicle radio receiver section, this is an easy hookup.

http://catauto.com/cat300dxl.html

http://www.nhrc.net/controllers.php
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VK5CQ
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Posts: 123




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« Reply #2 on: January 11, 2009, 06:04:25 AM »

Thanks for your quick reply...

I've had a very brief look at the 2 vendors you listed, and it seems that the lowest cost is still large.

We shouldn't need all the functions they include, as we are located far from town & city.

A very simple box with just an Autopatch function would suffice:

Maybe a CCITT or other tone access to start the call

A tone sequence (or "No voice from radio" time-out) to cause Hang-Up

A means of passing dial-tone through to radio [for some seconds], and passing operator-keyed phone number to the telephone line to dial the number

2-way VOX to let each side hear the other (phone-radio)
maybe via a low-power, full-duplex link that an old D700A can handle

Aren't there some -software- solutions for this problem? What are they? Are any Open Source?

Do they require less (hopefully much less) hardware (other than the radio, of course)?

Where are they? How to find the latest ones?

TIA
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AA4PB
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« Reply #3 on: January 11, 2009, 07:01:35 AM »

It should be a rather straightforward project if you have an operator present at the mobile end to set up the call and operate the PTT switch. It is possible to use VOX on the phone line but it can be problematic as it requires nulling a bridge after the call is set up (the setting changes depending on the distance of the lines). Years ago I ran a lot of HF phone patches for the military and found the manual PTT to be the most reliable.

Certainly you can do all the things you talk about such as remote dialing, PTT, etc. but is it worth the added complexity if you have a qualified operator present at the mobile radio site? In the U.S. you would have to have a control operator at the site anyway, unless you provide a secondary means of control.
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VK5CQ
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« Reply #4 on: January 11, 2009, 09:04:40 PM »

Thanks for your reply; you make good points.

Unfortunately, there was / is just one licensed Ham in the vicinity, and - until that changes - the person doing the examination and the Ham are one, with no one to activate the PTT.

I know Kenwood's TS-2000 HF/VHF/UHF radio can be remotely controlled by a handheld or even a TM-D700A.

So, perhaps it would be conducive to adapting to this application.

Ideally, however, a simple, DTMF-tone controlled interface box, that:

1. receives the number (from a handheld radio)
2. takes phone Off-Hook
3. dials the received phone number
4. uses, say, 2 x VOX and/or a full-duplex connection
   to connect the radio-based caller &
   the phoned doctor or hospital, and
5. on receiving a Hang-Up tone, sets phone to On-Hook
6. (optionally) signals complete/hung-up to radio opr.

would do the trick.

I'd think this was pretty simple to implement... yes?

Any takers? Anyone already done this kind of thing?
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W0IPL
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« Reply #5 on: January 12, 2009, 09:43:44 AM »

MFJ - does - in fact make such an item. It does require the operator to do the PTT thing, but that's not a problem and in fact makes sure there is a control operator present (required in US operation).

The model number is MFJ-624 @ $129.00 US.
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AA4PB
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« Reply #6 on: January 12, 2009, 10:11:06 AM »

To do the control functions you want you will need a processor such as a PIC and a DTMF decoder in addition to the audio coupling circuits. Full duplex will require dual band radios that can transmit on one band and simultaniously receive on another. It'll also require a transmitter capable of 100% duty cycle. Doing full duplex with Rx and Tx in the same band would require a diplexer and antenna separation, neither of which are generally very suitable for a mobile installation.

Simplex VOX will be pretty difficult to handle with no operator present because the level adjustment is rather critical. The issue is that the received audio placed on the phone line tends to trip the vox in the transmitter, cutting off the receiver so the thing cycles between Tx and Rx. To separate the audio requires a balanced bridge circuit that is dependant on the impedance of the phone line and that changes with different calls. Even when VOX is working correctly it is often difficult to get the person on the other end of the line to be quiet when it is not his turn to talk. While they are listening people tend to say "OK", "uh huh", etc. and that trips the vox, cutting off their receive ability.
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VK5CQ
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« Reply #7 on: November 10, 2009, 10:05:46 AM »

As I looked over a recently received VoIP Analog Telephone Adapted (ATA), from one of AU's VoIP providers, I noticed that it runs from 12 VDC (normally provided by an included power block).

Thinking of my earlier need for an AutoPatch system (cf original post of this thread), it occurred to me that it was possible (if not necessarily affordable) to use VoIP to solve this thread's issued.

Consider (and - please - critique) this system:

Router (for an ADSL or faster Internet service)
  :
Windows computer (at nearby base)
  :
[ICOM-supplied] USB cable
  :
ICOM ID-1 at base (10w, 1.2 GHz, 128 KB TCP/IP link)
  :
ICOM ID-1 on-site (10w, 1.2 GHz, 128 KB TCP/IP link)
  :
Windows notebook [netbook?] computer,
forwarding TCP/IP to its network port
  :
ATA
  :
any landline phone [that doesn't need a power block]

I know it looks like a Rube Goldberg machine ;-)
...but would it work?

Yes, use of ICOM ID-1's places this project on the "way too costly" list; a long-range WiFi LAN that reliably connects base computer with on-site notebook
would do (eg, an existing community-run mesh N/W,
with some omni-directional access points within reach?)

(Our VoIP provider charges just AUD $ 0.10 for calls to landlines, of up to 1 hour in length.)

If there were a cheap (base to site) TCP/IP link system, would this be likely to work?
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VE3EMP
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« Reply #8 on: November 15, 2009, 12:05:57 PM »

A Laptop (A P4 should be sufficient) and a soundcard interface with this software http://www.echolink.org/sc/
 (Echo Station) should work.

73
VE3EMP
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VK5CQ
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Posts: 123




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« Reply #9 on: January 25, 2010, 05:29:09 PM »

You seem to be assuming we have Internet in the Outback. (We do, but only in staff homes & the admin office; we were going to install it in the store, to help get folks who've never had access to Internet up-to-speed with it, but that plan fell through.)

There isn't any low-cost, easy-to-schlep or mobile (2-way satellite) Internet systems available there, nor were there any extra laptop computers available, at the time. (And our Sat.Phones were off-site, with others.)

--- This is an Remote / Outback / Bush story...

Just a reminder, this thread addresses the needs for phone patch facilities, at / near an Aboriginal community, in which very few people have telephones in their homes; they use one of 2 open-air public phone boxes or try to humbug the use of the shop's phone from whoever's manning the store.

Sat.phone would be an obvious solution, but cost & the availability of a phone made me think that Ham Radio could provide a better solution, that would also work off-site, as far as radio-range to my home (at the time) would allow a phone-patch to work.

Medical emergencies happen anywhere: on-site, on the road, on nearby work sites, and there has been a passenger train derailing in that area, in recent past, which required MedEvac's, etc. of passengers & others.

Bush fires might also give rise to the need for a Radio-to-POTS (telephone network) connection by protable autopatch.
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VE3EMP
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« Reply #10 on: January 25, 2010, 09:52:00 PM »

Perhaps one should actually follow the link and read the information referred to. The software is called echostation not echolink, it is only written and supported by the same people. This package is essentially a simplex repeater and autopatch program, not a voip program and not dependant on the internet.
 As for spare laptops, Pentium 4 machines are several generations out of date. Check ebay (I see several suitable ones for under AU $90) with a suitable voice modem the computer connects to the POTS line and with a soundcard interface to the radio of your choice. A simple off the shelf solution.

I have used this system in Northern Ontario (an area of Canada easily if not more remote as the Australian Outback and sharing the same communication issues)So believe it or not do actually have a clue about the issue you are trying to solve.
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VE3EMP
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« Reply #11 on: January 25, 2010, 09:54:53 PM »

Perhaps one should actually follow the link and read the information referred to. The software is called echostation not echolink, it is only written and supported by the same people. This package is essentially a simplex repeater and autopatch program, not a voip program and not dependant on the internet.
 As for spare laptops, Pentium 4 machines are several generations out of date. Check ebay (I see several suitable ones for under AU $90) with a suitable voice modem the computer connects to the POTS line and with a soundcard interface to the radio of your choice. A simple off the shelf solution.

I have used this system in Northern Ontario (an area of Canada easily if not more remote as the Australian Outback and sharing the same communication issues)So believe it or not do actually have a clue about the issue you are trying to solve.
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AA4PB
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« Reply #12 on: January 26, 2010, 06:07:36 AM »

I hadn't heard of echostation before but from the web page it does look like a ready-made solution.

A custom solution might be to use a 2M/440 transceiver on the POTS end running full duplex so that no T/R switching is required on the "operatorless" end. A DTMF decoder would take care of POTS dialing and control of the transmitter. The operator with the HT would always be able to terminate the call and shut down the remote transmitter. If someone had a full duplex capable HT he could just hold down the PTT and talk like using a normal telephone. It would require some custom hardware (DTMF decoder and audio interfacing) but it wouldn't require a computer at either end.
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ALCO141
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« Reply #13 on: January 26, 2010, 11:48:43 AM »

so how did you set up your echostation, what radio did you use, how did you hook the laptop to the phone line, give us some details os we would have an idea as to how this would be put together.

alex

kc9pwt
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KC2TLS
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« Reply #14 on: February 17, 2010, 06:26:19 PM »

Unfortunately it looks like the autopatch as part of echostation really is not functional with today's radios.  I tried to set my IC2200H up, and ran in to the problem with the computer locking the transmit open.  I e-mailed the programmer and got a quick response that the autopatch really shouldn't be used, and was only possible to use with older FM radios (crystal) that had been modified for fast TX/RX switching.

If anyone has another source for a "cheap", easy autopatch I'm all ears!  I'm no where near as remote as the outback, but still there is no cell phone service but great repeater coverage in the mountains (repeaters have power but no phone line).
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