System Sensor 2WTA-B + COSMO2W question


New Member
Hi all,
I apologize if this question has been asked on this forum, but a search couldn't answer my fairly generic questions.
1.  I'm currently sizing an auxiliary power supply for 5x 2WTA-B, 2x COSMO2W sensors paired with a COSMOD2W module.  I'm trying to calculate the max. power consumption for the loop.  If I'm reading the datasheets correctly this is what I've surmised:
Since it'll be used with a COSMOD2W interface module, it'll be 30mA for the alarming 2WTA-B, plus 12mA for all other 2WTA-B units.  It'll be 20mA for each COSMO2Ws.
If the COSMO2W is the one in alarm, it'll be 50mA for the alarming COSMO2W, 20mA for the non-alarming COSMO2W, and 12mA for all 2WTA-B.
Then add in about 174mA max. alarm current to the COSMOD2W.
Am I getting this right?  Basically I'm not understanding the when a unit would go into "Direct Power" draw mode and my assumption is when it's in alarm state.
2.  When connected to the COSMOD2W, I understand the loop is connected to the IDC+/- connections, but do I have to connect the Style-D connections as well?
Thanks - appreciate any help.  I'm fairly versed in burglary aspects of the alarm but very little in smoke/CO 2-wire/4-wire loops.
Style D would negate the need for an EOLR and allow the loop to function even if it is broken. Very common in high risk or mission critical installations.
I'd have to look at the sheets but usually with SS modules and detectors the current is inherently limited to the max of the connected module and additive for the detectors in alarm/reverse tandem ring state.
Style D is not really necessary in 99% of the cases.Usually makes it more difficult for a novice unfamiliar with wiring methods.