I agree there may be a wiring problem or issues on the Telco side of the switch.
Another issue we have found in our repair lab with the ACS R4.0 processor is on the main circuit board. Avaya had a specific problem during manufacturing of the R4.0 circuit board where the protective coating they apply to the board - during/after components were auto heated soldered in place - was defective as this specific run of boards develop corrosion spots over the entire front and back of the board. This causes many circuit level problems translating into ones such as the one ZOOMINCO has described.
Some R4.0 processors were DOA out of the box if they were held in distribution long enough and some developed over time if they were installed shortly after production. We had a copy of an internal memo from Avaya we obtained describing this problem but I can't locate it right now.
Depending on the problem and degree of board corrosion there is a process to repair about 30% of these boards - in our experience. We have tried many solutions to effectively "cleanup" these ACS R4.0 boards. The only process that has produced any results has been "soaking" the board completely in a few inches of gasoline ... grade doesn't matter

- for a few days then carefully brushing the entire board until the corrosion is removed. It is time consuming and again only about 30% effective.
Be careful if you open the shells that you don't void a valid warranty you might still have available from your vendor if you break their warranty label.
Does anyone else know any other tips on cleaning these ACS R4.0 boards?
NOTE: This corrosion only occured on true ACS R4.0 labelled processors - not on "upgraded" older boards as the corrosion is board related not software version related.
Andrew Roach
President - Drew Telecom Group, Inc.
Lucent/Avaya Voice Mail-Component-Transtalk Repair Specialists
Lucent/Avaya Telecom Brokers/Resellers
drew@triton.net
269-685-5400 - voice
269-685-5500 - fax