is a device which is used to track arrhythmia
meaning irregular beats which are hard to track as being irregular in nature and its not a constant phenomenon hence the constant 24hr monitor is needed to track it ( like antivirus software monitor your online activity and protects your computer from virus attack).
THE ANSWER TO YOUR QUESTION IS
THE "DR200/HE" Is the model number of the Holter monitor instrument and is made by
NorthEast Monitoring, Inc.
Mostly what you have seen on the screen is the model number of that machine type on the screen of the monitor LCD.
If in need of more information here is the link you can have the information about specification of the device
HOPE IT HELPS!!