The Hayes Micrmodem II modem. The important addres locations (assuming card is in slot 2) are in this table from the article "Pascal Techniques" in the Call-A.P.P.L.E "All About Pascal" issue: Address Read Write $C0A5 Modem Status Modem control $C0A6 ACIA status ACIA control $C0A7 Receive data Transmit data The modem register bits: 7 Off hook 6 not used 5 not used 4 self test 3 clear to send 2 mode select 1 transmit enable 0 bit rate select modem status bits 7 ring indicator (negative enable) 6-0 not used ACIA Control 7 receive interrrupt enable 6 transmit control 5 " " 4 word select 3 " " 2 " " 1 counter divide select 0 " " " ACIA status 7 interrupt request 6 parity error 5 receiver overrun 4 framing error 3 clear to send (neg. enable) 2 data carrier detect (neg. enable) 1 transmit data register empty 0 receive data register full