Problem with Phone system in OZ

[TheVampire]

OZ as in Australia, that is.

We have a telephone intercom system, that can be switched from local mode ( intercom rings local phone it is connected to ) to remote mode ( intercom will dial outside phone # and wait for answer, and redial on busy ).

All works fine here in the USA, but when attached to the phone systemn in Australia, it works good in local mode but in remote the volume levels are way way lower than they should be.

Anyone have an idea what the problem might be? Is there some sort of amplifier box we can connect up to the unit that will boost the signal? Are Australian voltage levels that much different than US?

Any help or suggestions will be greatly appreciated!

Robert

 

[jerryreeve]

digging back in memory but I think that australia may be using 900 ohms termination vs 600 ohms term in the US. check on your equipment and you may have a switch that will allow you to change the termination.

How does the lines sound from a local phone set up for the local telco?



JerryReeve
Communications Systems Int'l
com-sys.com

 

[TheVampire]

The local phone sounds fine when used on the same phone line, so we've pretty much traced it down to our equipment.

Your suggestion about the line termination seems worth looking into, so I'll pass that along.

Thanks for the reply,

Robert

 

[oldgoat47]

If the system is set to 600 ohms it should work ok in Aust
You don't say which type of system it is but I know some of them have pad settings to compensate for short and long lines.
Bob McDermaid QLD Aust.

 

[jerryreeve]

I wasent sure of australia's standard so thanks it should only have been a few db loss anyway.

JerryReeve
Communications Systems Int'l
com-sys.com

 

[TheVampire]

It's basically a home intercom/phone interface unit made by DFE Inc that we have adapted for use in our security system. The master unit is placed in-line between the incoming phone line and the phone itself. The master then has substations that can connect to it, that consists of a speaker and pushbutton. A transformer is used on the speaker to step from a high impedance to a low impedance, and this allows the substation to be up to 3/4 of a mile from the master.

When the button is pushed, the local phone will ring with a special double ring ( to let the person know it's an intercom call and not a regular phone call ), and when the phone is answered it is automatically connected to the substation that was used. It's half duplex, so when the user at the phone is talking they cannot hear the substation.

In remote, a button push initiates a call to a programmed phone #. When the remote phone is answered, a series of beeps is heard at the phone, and the phone user has to push the # to connect to the substation. After that it works the same as local mode.

I'm travelling down to Sydney in a few weeks for other business, and might have to go do some in person troubleshooting at the site in question, so any information I have beforehand is very nice!

Thanks,

Robert