Batboard

Hi There,

I have searched the postings for the answer to this enquiry but there still seems to be conficting answers and I wonder If I asked the question in a slightly different way if the answer would be a little clearer to me.

I have a Astro Saber VSELP, it is operating in C4FM, there has been fitted a DVP/ DES-OFB module in this radio. It encrypts in analogue no problem DVP but in Digital the radio emits a constant low tone from the speaker when the PTT is pressed. Almost how you would expect a 'receive only' channel to operate. With the encrypion select switch back on clear the radio transmits and recieves Digital as it should.

The module will accept both a DVP and a DES-OFB keyfill from the appropiate KVLs and does not give any Key fail display or audible error signal in either Analogue or Digital modes.

I have checked the CPS settings over and over and unless I have missed the real obvious I would bet my money on that a VSELP radio in Digital will not work with a DES-OFB module. Can some one please confirm this.

However, what I cant understand is why it will not use the DVP algo in the module to encrypt the digital signal as appears to be the interpertation of reading some previous postings on this subject. Again, through trial and error and reading conficting sometimes 'hazed' replies I would assume that if the module was DVP-XL/DES-OFB then although OFB would not be compatible for VSELP digital it would have infact use the DVP-XL algo and encrypt my digital transmission. Again I would be appreciative of confirmation of my assumptions.

Many Thanks in advance Tom.

Thanks,

The radio is not flashed mulitkey, so fine on that.

So does that mean that the second algo in the line up of DVP/DES-OFB is applied only to digital traffic and the first DVP applied to analogue traffic?

I have read in the previous postings that a DES brick will work on both Analogue and Digital selections. Or is this true of -XL algos only which would explain why my radio isnt using the DVP element for digital encryption.

So If i was to get a plain Jane DVP or DVP-XL brick with no second algo (OFB) it will work for me on both Analogue and digital modes. ? Surley if the radio is not seeing multikey flash why does it not apply the DVP to the digital tx.

Mmmm Strange things these modules !!

Regards and thanks again Tom.

Hi again,

I have now read that posting you directed me to a couple of times now and I gather that the difinative answer is:

As my module is DVP/DES-OFB and the OFB KG2 cannot be accessed by a single key radio, it is not doing any encryption in Digital mode as DVP (KG1) is not supported as a 'digital useable' algorythm. For it to function for me on both analogue and digital modes it needs to be -XL. This would explain perfectly my situaton.

If it were that I was using DVP-XL/DES-OFB as before in this radio, DES-OFB KG2 is not accessable but the KG1 DVP-XL is, and because it is accepted as a useable algo for Analogue 'and' Digital it will encrypt on both modes, unlike the DVP KG1 that only works on analogue.

Correct.... Phew I think we got there in the end.. A mine field of terminology and options on this one me thinks !!

Thanks Tom