>business - we write software for ISP for a living; our ISP operation is
>just an alpha test site for our products) and we don't have enough lines to
>fill two PM3s, but enough so that one PM3 is not enough.
>
>At that scale, purchasing a second unit to use it at less than half its
>capacity seems like a hefty overhead. If we had enough dial-ups to fill 5
>PM3s, then the equation would be quite different.
Don't lease or buy the extra modem cards, then..... You can get a
"second" PM-3 with only 16 ports, for example, for FAR less than $15,000.
Since PRI comes in "23 at a time", you need to be thinking in terms of
multples of 23 in any case.... 23 or 46 in one PM-3, up to 69 in a second
PM-3 with just 24 modem cards....