XTS5000 Replace battery Loose keys?

[Java]

I need to replace the batteries in about 7 XTS5000 model 3s, There all keyloaded with IKR enabled.
IF i remove the UCM to get access to the cell battery will the UCM drop its keys>?
All i am doing is swapping batteries out with old in with the new. DONOT want to spend time rekeying
Also, Can i clone the keys with my t3011xx that way if i do blow the keys i can just reload em?

[N4DES]

If you have IRK enabled it shouldn't drop the keys. I have transferred keyloaded secure boards between XTL mobiles that had IRK enabled (not with the carrier) and didn't lose any.

Clone the keys? You can't pull an algo out of a radio once programmed if that is what you meant.

[Tishers]

Encryption keys were never intended to be read back out of the module. Imagine the glaring security hole in a system if someone could temporarily gain access to a legitimate radio and to lift the encryption keys out and then to drop it back in a different radio.

It is a one-way action of writing to the module with the keys. If your coin battery is in good shape you should not lose the keys if all that you are doing is swapping out the main battery. I just would not leave the radios without the main battery (or a charge) for so long that the coin battery dies.

The coin battery is replaceable, it is a Pain in the ^$$ to get to. As the radios in the Astro XTS series get older you might want to replace the internal battery, maybe once every 5-10 years.

[MTS2000des]

The lithium battery is to power IRK? News to me. I've had XTS5Ks in storage with no main battery and the UCM held the keys just fine while this battery was dead. IIRC it is just to maintain the clock.

[Tishers]

That has me interested now; I will chase down the schematics to see exactly what is juiced off of that battery. Maybe the encryption board uses NVRAM (non volatile) and does not require a wetting voltage to hold the data.

The battery is actually a rechargeable Li-Ion in a miniature coin style. It is on the VOCON board and has a generic battery model number of "MS621". It is a 3 V, 4 mA/Hr battery (very tiny) and should be charged by the main battery. Therefore you would not want to leave the radios without main batteries or a charge for a really long time because the coin battery will also discharge and dump the radio programming.

Unless the battery is "missing" or in such a non-functional state that it is essentially not there it is hard to imagine someone needing to worry about swapping the main HT battery and in that 30 seconds or so the little coin battery could not hold a charge for "that" long.

I guess you could go the "extra" distance and just buy a MS621F battery; it is rated to 5.5 mA/Hr (whoo-hoo, big deal! ).

---- edit---: Now this is interesting, this tiny battery is only rated to 200 charge/discharge cycles. You would not want to be yanking the batteries out every week for a few days at a time.

https://media.digikey.com/pdf/Data%20Sh ... Series.pdf

[MTS2000des]

When I took my current position with the agency I am working for, I had about found several XTS5Ks that were sitting with no primary battery attached for years (at least 7 years or more, and the radios were made in 2003/2004), several had UCMs and keys loaded, all of them still had the keys and did not show a KEY FAIL. The RTC of course, was not working.

It seems logical (without consulting the SMs) that if the on board battery was intended to backup the TEKs wouldn't it have been located on the UCM itself? Radios that shipped without UCMs have them as well as XTS2500s (remember when the original 2500 was rolled out it didn't even support hardware encryption, hence the keypad board containing all the crypto stuff as an afterthought)

[mike m]

The coin cells only purpose is for the radios clock feature, it has nothing to do with ENCRYPTION KEY RETENTION

[Tishers]

Thanks for setting that straight; I guess we can say that we have a definitive answer on key retention during battery swap-outs or if the coin memory battery is dead.