Dial-up BBS with an Acoustic Coupler on a Commodore PET 2001-8

In this video I login to The Hidden Reef BBS on a Commodore PET 2001-8 using an acoustic coupler (Actam C300A), PETTERM, an RS-232 to TTL level shifter, an Obi200, an old Bell phone, and some careful wiring. After some adjustments to the gain trimpots on the coupler it only occasionally drops characters and doesn't seem interrupted by the sound of quiet conversation. I tied RTS to the 5v line on the level shifter to clear up compatibility issues with the modem. The phone needed polarity settings reversed in the Obitalk interface to ring.