GE MAC 1200 Service Manual page 34

RS-232 Interface
Buzzer
2-16
Functional Description: PCB Control CS_CI
The MAC 1200 resting ECG analysis system has an RS-232 interface accessible
with a 9-pin Sub-D connector.
Except for the RS-232 driver chip, the interface is integrated into the control core of
the MPC855T.
The interface has the following attributes.

Hardware handshake with the signals RTS and CTS.

Software handshake with XON/XOFF.
 Transmission speeds from 4800 ... 57600 Baud.

Maximum input voltage range: ±15 V.

Minimum driver output voltage: ±5 V.
 Maximum ESD interface protection: ±10 kV.
The MAC 1200 resting ECG analysis system provides a remote start input on the
RS-232 interface. The MAC 1200 resting ECG analysis system US device
additionally provides a modem power supply output on the RS-232 Interface.
The buzzer is an integrated signal generator with fixed frequency, directly operating
from the +5 V logic power supply.
Activating and deactivating is controlled with the signal SPEAKER.
MAC 1200 resting ECG analysis system
2012250-095
Revision D