This depends on the number of digits they will be sending you and the number of digits in your Merlin. Basicly, with a "Setup Space" configuration you'll want to stay away from ranges starting with "0" (the Operator) "7" (the default number for extensions, adjuncts, calling groups & paging groups, though the range 7500-7699 is available) "8" (the default number for LDN,trunks, pools, call park) and "9" (the ARS dial out code). With the exception of "0", you could renumber any of the other banks to match your needs. Or be creative, for instance, say you DID range is 8100 thru 8199, you could renumber the default trunks (801-880) to 8900-8979 thus freeing up the ranges 8100-8899.
franke