[NHRC-user] NHRC-5 with battery backup

[jeffrey at nhrc.net]

Hi,

Make the LED in an optoisolator light up when the AC is on.  Normally this
might come from the DC power supply output, but if your supply has
integrated battery management it is not so easy.  You could use a
wall-wart and current limiting resistor to light the LED.

Use the photo-transistor in the optoisolator to pull the EXP input low (to
ground) when the AC is on.

You could also use a small relay to close the EXP input to ground when the
AC power fails (use the normally closed contacts and energize the relay
coil from the mains...)

Jeff


> Greetings to all:

>

> This is my first post to the list.  I've been thoroughly enjoying getting

> to know a NHRC-5 controller that I purchased a couple of years ago, but

> have finally been in a position to get operational.  It has been lots of

> fun and learning.

>

> I'm trying to configure the repeater to switch courtesy tones when the

> repeater goes onto battery backup.  Switching to battery is handled by a

> surplus Samlex BBM-1225.  It handles seamless switching and charging of

> the battery.  In the past we used a Motorola controller that would sense

> the loss of voltage from the power supply, and change courtesy tones to

> alert users to keep it short.

>

> I see that EXP3 and EXP4 can be used to change courtesy tone, but I am a

> little confused on how to use them.  I see that they need to be "pulled to

> ground" how exactly to do that is where I am stuck.

>

> Any thoughts would be appreciated.

>

> 73,

> Jay - KD4BPZ

>

>

>

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