Conventional TENS
(Local Relief)  This is the most proven mode of TENS and is usually most effective for relief of "local" moderate to superficial myofacial type pain.
Modulation -(SAM) Simultaneous Asynchromous Modulation
(Local relief) This is an asynchromous (out-of-sync) combination of rate and width modulation.  This is a variation of conventional TENS, which may offer a "subjective" variation in sensation.
BURST
(Systemic relief)  Burst TENS is a variation of low rate TENS with a more comfortable delivery of "bursts" of low frequency versus "beats" of low frequency.  This method appears to be more acceptable for patient compliance. 
MEDA 2500 Burst
This is a new mode of TENS that is designed to emulate clinical medium frequency stimulators.  Medium frequency may allow for easier tissue penetration by decreasing resistance.  This mode of TENS might best be used on deep, difficult to reach pain sources where highly resistive tissue, ie, bone, fat, scar tissue.

Amplitude Output
Two constant current outputs, each independently adjustable from 0-60 milliamps.  Constant current into a load impediance from 500-2000 ohms at normal amp settings.
Output Waveform
Rectangular pulse with "0" net D.C. value.
Pulse Rate
Fully adjustable from 2-150 pulses per second.
Pulse Width
Fully adjustable from 50-250 microseconds.
Burst Mode
Conventional burst mode consists of 7 pulses at 100 pulses per second.  Bursts occur twice every second.
Modulation Mode
Rate is modulated from rate post set value of 50% of the set value.  Width is modulated from width set value to 50% of the set value.  Modulation is a linear ramp-down, ramp-up mode without any discontinues in a 4 second envelope.
Channel Interaction
Less than +/- 1% with second channel into 1,000 ohm load.
Channel Phase
Both outputs are in phase.