208V to 208/120 transformer

You get 208 volts coming in via an L6-XXP plug. Output is an isolated
120/208 volt split phase. So how would this be done?

http://www.apcc.com/products/resource/include/techspec_index.cfm?base_sku=SURT003

One possible idea is:

|<------- 208V input ------->|
| |
* *
\/\/\/\/\/\/\/\/\/\/\/\/\/\/
===================================
/\ /\/\/\/\/\/\/\ /\/\/\/\/\/\/\ /\
* * * * *
| | | | |
A B C D E

A-C = 120V
C-E = 120V
B-D = 208V
A-E = 240V

C might even be bonded to ground.

Another possibility is that it is not really 120/208, but some compromise
voltage like 112/224 output (so they don't have so many transformer taps).

How would I be able to determine exactly what they are doing? They do not
seem to provide schematics for anything.

 

Actually, it may well be relevant. 208V output may only be available
with 208V input. IOW, only a center tap on the secondary (no
connections B&D).

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