JP,

Since vpn concentrator console port is rs-232 complient you can buy two DB9 female to rj-45 adapters, one for the concetrator and one for the PC to use in COM1 port, then use a regular straight through CAT5 cable , this is the way I do it, and is practical as suppose to use the straight through rs-232 serial cable.

http://www.sealevel.com/product_detail.asp?product_id=787

As for the regular cable that concentrator comes with you can use this.

http://www.stonewallcable.com/product.asp?dept%5Fid=35&pf%5Fid=SC%2DS9%2DFF

Adidtional info for your initial concentrator seup -

http://www.cisco.com/univercd/cc/td/doc/product/vpn/vpn3000/3_6/getting/gs2inst.htm#1050260

Regards

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