Yes... A 3526 can be hooked to a PBX. The PBX needs to provide network-side signalling to the 3526. The 3526 supports a number of PRI signalling types including 5ESS, 4ESS, NI2, DMS100, etc... so it should be pretty flexible in working with various PBXs. Note, that you may also need a CSU. Hope this helps