Communication With A Pc; Figure 20: Data Port Pin Layout - Nellcor OXIMAX N-595 Service Manual

Data Port Interface Protocol
Communication
With a PC
98
Table 18: Data Port Pin Outs
Pin
9 RXD- (R-422 negative output)
10 Signal Ground (isolated from earth ground)
11 Nurse Call (RS-232 level output [-5 to -12 VDC with no audible
alarm] [+5 to +12 VDC with audible alarm])
12 TXD- (RS-422 negative output)
13 AN_Pulse (analog pulse rate)
14 AN_Pleth (analog pleth waveform output)
15 Nurse Call Common for Dry Contacts
Note: When the instrument is turned off, the contact at pin 7 becomes
closed and the contact at pin 8 becomes open.
The pin layout is illustrated in Figure 20 on page 98. An AMP connector is
used to connect to the data port. Use AMP connector (AMP P/N 747538-1),
ferrule (AMP P/N 1-747579-2), and compatible pins (AMP P/N 66570-2).

Figure 20: Data Port Pin Layout

When building an RS-422 cable, a resistor (120 ohms, 1/2 watt, 5%) must be
added between pins 1 and 9 of the cable. The end of the cable with the resistor
added must be plugged into the N-595. This resistor is not necessary for
RS-232 cables.
The data cable must be shielded (example: Belden P/N 9616). Connectors at
both ends of the data cable must have the shield terminated to the full 360
degrees of the connector's metal shell. If rough handling or sharp bends in the
cable is anticipated, use a braided shield.
Data can be sent from the N-595 to a PC by using a data cable with a Null
modem connector installed between the instrument and the PC. Select the
ASCII Comm protocol (see Communication Protocol page 91). Data sent to
the PC is serial, 8 data bits, no parity, 1 stop bit XON/XOFF flow control and
is space delineated. When the connection is made, real-time data will be sent
to the PC. A new line of data will be sent every 2 seconds. The information
presented will be the same as described in Real-Time Printouts later in this
section.
Signal