Probably an old Tie Ultracom 2260B. What a wonderful system, you could do stupid contradictions in the programming overlay (1-49) which wouldn't let you out of programming unless you crashed the switch, leaving it for the next poor slob to find when he ventured on site to change the time for daylight savings time. Not to mention the fact it stopped processing calls while in programming at extn 10
They didn't have analog station cards so would have required a proprietary digital integration. I would doubt any voicemail system would support that type of integration. The forwarding to voicemail wouldn't work properly on a no-answer condition and may not even provide enough information to the voicemail system to sent it to the appropriate mailbox.
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