TX Inhibit on XPR 8300?

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n9dki
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Posts: 8
Joined: Wed Mar 04, 2009 6:45 pm
What radios do you own?: MSF5000's, MTR2000's, XPR8300

TX Inhibit on XPR 8300?

Post by n9dki »

We are trying to address some RF exposure issues at our shared repeater site. Our MSF5000's have TX Inhibit inputs to shut down the PA by grounding the pin, is there any way we can shut down the PA on an XPS 8300, short of pulling the 120 VAC plug and battery connector? Is there any possibility that the EMERGENCY SWITCH INPUT, pin 23 on the rear accessory connector, could be configured as a TX Inhibit?

Thanks for whatever wisdom you might share.

N9DKI
RFguy
Posts: 1357
Joined: Wed Dec 21, 2005 6:17 am

Re: TX Inhibit on XPR 8300?

Post by RFguy »

There is a disable input. We use it for testing desense. Allows us to disable the TX when doing RX checks. Not sure what pin it is.

If you can't find it, PM your e-mail and I'll e-mail a codeplug that has it programmed into it.
Wiregeek
Posts: 61
Joined: Thu Nov 06, 2014 9:53 am

Re: TX Inhibit on XPR 8300?

Post by Wiregeek »

It's configurable. From the MotoTRBO CPS, pin 17 is settable to the following (as well as a lot of others)

Repeater Knockdown This is an input line, that when activated, will disable the internal repeat path of the repeater for as long as the pin is activated. An external device can then control when the repeater keys-up (applicable to Analog mode and Dynamic Mixed mode, Repeater configuration only). Note: In Dynamic Mixed mode, this feature is not supported during an ongoing digital transmission.

Disable This is an input line, that when activated, disables the repeater. When this is de-activated, the repeater is re-enabled. Note that the repeater will reset before changing its state (applicable to Repeater configuration only).

Reset This is an input line, that when activated, resets the repeater (applicable to Repeater configuration only).

TX Power Level High This is an input line, that when activated, sets the repeater to use the high power level for TX transmission. When de-activated, the repeater uses the low power level for TX transmission. Note that the repeater will reset before changing its TX power level (applicable to Repeater configuration only).

FCC Type 2 Monitor This is an input line, that when activated, prevents the repeater from keying up and from repeating inbound calls in a IP Site Connect environment (applicable to Repeater configuration only).

Football Knockdown
This is an input line, that when activated, disables the receive and transmit operations of the repeater for as long as the pin is activated. CWID will not be transmitted while this option line is active (applicable to Single Site Digital mode,

These are options for the accessory pins, and like any of them can be configured to be high level (5v) or low level (0v) inputs. I recommend setting it as a low level input and then grounding the pin to activate. There is a pull-up resistor in the radio that will 'default' the pin to ~5v if nothing is connected to it.

Looking at it, I'm not sure which option would best suit, but I'd probably start at Knockdown.
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