EBME Forums Forums Maintenance Technical Assistance Electronic transfer of data from NIBP monitor

Chances are that RS-232 will be the protocol used. If you have the time, patience, and a few bits of test kit (which you can make up yourself if you're really keen), plus a bunch of leads (as Robert mentions), you can establish what's going on by experimentation. The difficulty could lie in getting the device (NIBP monitor etc.) to give up, that is send, its data.

As an aside, this sort of playing around is where good old kit like the BBC Micro can come in very handy (for those of you who remember them). That and "old" PC's ... typically of the so-called "Pentium 1" 100 MHz classic PC running MS-DOS. Either way, and obviously, the computer used needs to have a serial port.

The data I have here is on page 139 Appendix Cfor the procare.

Pin 1 Common
Pin 2 Inverted TTL Tx Data
Pin 3 Inverted TTL Rx Data
Pin 4 5 volts
Pin 7 Common
Pin 8 Remote Alarm
Pin 11 Rs232 Tx data
Pin 13 Rs232 Rx Data

All other pins no connection.


For the pro 1000 Page 167 of the Appendix

P1 Ground
P2 Inverted TTL Tx Data
P3 Inverted TTL Rx Data
P4 Fused 5 volt
P5 Fused 12 volt
P6 Serial Level control
P7 Ground
P8 Remote Alarm
P11 RS232 Tx data
P12 Port enable Control
P13 RS232Rx data

All others no connection

Thanks for that, Mate. Interesting. See how similar they are (and why not)? I wonder if the early Dinamaps use essentially the same configuration? My guess would be that they do.

How about the Accutorr. Does anyone have the pin-outs for those? In addition to the usual RS-232 connections, the latest ones have something called DIAP, apparently. Yet something else to fiddle about with, then (life's too short)!

Meanwhile, I hope you don't "get into trouble", Billy. You know, for spreading "sensitive" information on the forum!

Looking again at those pin-outs, they clearly don't follow RS-232. Which, of course, is not unusual (and is in fact, as far as my "research" has shown, the norm for medical equipment). That is, just because a bit of kit has a 9-pin (or 25-pin) D-shell "serial" connector on the back, don't assume that it's RS-232 (even though labelling could well give that impression).

As others have already said, the only sure way of establishing what's on those pins is by referring to the manual. And (for the more adventurous) getting out the multimeter and oscilloscope.

Often there are test voltages on there. Typically battery levels, and other such useful information.

Luckily, RS-232 (and similar) driver circuitry is generally tolerant of misconnections, and will usually survive even a drive signal being connected to ground, or two drive signals connected to each other. In any case, if the serial interface between two devices is not operating correctly, simply disconnecting the cable joining the equipment will generally solve the immediate problem!

But ... what we need is a complete list of serial pin-outs for all medical kit. I embarked on jotting them down in my notebook many (many) years ago, but must have become distracted somewhere along the way (and the notebook itself is long gone).

So please, pin up those pin-outs when you have a few spare moments.

Have fun! After all, that's what "standards" are for!

For instance, here's one that I just happen to have to hand. The Rigel 277 Safety Tester, which uses the standard 9-pin D-shell connector:-

Pin 1 - Not connected
Pin 2 - Rx
Pin 3 - Tx
Pin 4 - DTR
Pin 5 - Zero volts
Pin 6 - Not connected
Pin 7 - Zero volts
Pin 8 - Not connected
Pin 9 - +5 volts

Baud rate : 9600
Data bits : 8
Start bits : 1
Stop bits : 2
Parity : none

Rx : Received Data
Tx : Transmitted Data
DTR : DTE Ready
DTE : Data Terminal Equipment ... almost always a PC or similar
DCE : Data Communications Equipment (but originally Data Circuit-terminating Equipment per RS-232 ... and back then, almost always a modem)

For comparison, here are the "offical" 9-pin RS-232 pin-outs:-

Pin 1 - Received Line Signal Detect
Pin 2 - Received Data
Pin 3 - Transmitted Data
Pin 4 - DTE Ready
Pin 5 - Signal Ground
Pin 6 - DCE Ready
Pin 7 - Request to Send
Pin 8 - Clear to Send
Pin 9 - Ring Indicator

... so in this case, the Rigel 277 connections are a near approximation, which is all nice and proper!

See here for some nice information about RS-232 connections. There's even a forum, for those who are really keen.

And (just for fun) here is one more. This time it's the Alaris GH Syringe Pump. Here the literature actually mentions RS-232 (which it clearly isn't in actual fact)!:-

Pin 1 - Nurse call relay (normally closed)
Pin 2 - Transmitted Data Tx
Pin 3 - Received Data Rx
Pin 4 - "Power input" DSR
Pin 5 - Ground
Pin 6 - Not connected
Pin 7 - Power Input CTS
Pin 8 - Nurse call relay (normally open)
Pin 9 - Nurse call relay (common)

Baud rate : 38400
Data bits : 8
Start bits : 1
Stop bits : 1
Parity : none

Nurse call realy contacts rated 1A at 30V

CTS : Clear to Send
DSR : Data Set Ready

Note that Pins 2 and 3 appear reversed (when compared to RS-232). But don't forget that we're now looking at DCE (what used to be the modem)!

OK, that's it for now (lunch time)!

This link has some value.

Note that (as we have seen) Pins 2 and 3 are the main ones of interest, and:-

For those who still don't know their RS from their UART ... it's all here.

Nothing more for me to say on this topic.