Subject: TBR 21- 60 mA max. loop current
Hello all, I am brand new to this list.....so please be gentle 8-) My concern is the possible increased power dissipation re- quired by the terminal equipment (TE) when connecting to the EU PSTN. Assuming the worst case of: the test model 50.0V (could even be higher in practice) battery and 230 Ohm battery feed resistance, and short (co-located) loops, this equates to 50.0 -.06A x 230 = 36.2V across the TE T,R port. Now, since Ohms (not to mention Kirchhoff's) law has yet to be repealed, results in a maximum per port power dissipation of P(T,R) = 36.2V x .06A = 2.172 Watts! This is about (in our case) 3x the heat dissipation that we ob- serve when interfacing the North American 48V/460 Ohm battery feed model. Has anybody out there also "taken the heat" 8-) and if so, been able to defy Mr. Ohm and/or Mr. Kirchoff and somehow dissipate less heat (and still meet TBR 21, of course)? Thank you...cool it...and.. cheers, bob lee
