VPN Module problem in a Cisco 1721 router

I have a Cisco 1721 router and have tried to install a VPN module MOD1700 - 3DES and a show diag indicates the module is not working.  The module works fine in a 1720.  I think I have loaded the correct IOS image c1700-k9o3sy7-mz.123-9.4.bin
I also tried c1700-k9o3sy7-mz.122-4.T5.bin - the same image as in the 1720.

The 1721 has 96 meg of RAM and 16 meg of flash, an SDSL WIC and an Ethernet WIC.

From what I have read the VPN module should work in a 1721, have I missed something?
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snarler45Author Commented:
I have answered my own question so for the interested here is/are the answer(s):

1) There are several versions of the VPN card for the 1720/1721. The two I have are 73-4586-02A0 and 73-4586-02B0.  The 02A0 will work in the 170 and 1721, the 02B0 will not work in the 1720 but will work in the 1721.  So if you buy on eBay make sure you check.

2) The 12.3 images supporting IDS FW IPSec etc will not run in the 1721 - the release notes reveal this but are tricky.  12.2 images work well in both the 1720 and 1721.

Cool I am my own expert.
Question answered by asker or dialog valuable.
Closed, 500 points refunded.
ee_ai_construct (replacement part #xm34)
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