Hard to make a table here.
List shows your pin + wire colour, then Function, then where to connect this wire on USA TCU (TCU pX), and the USA TCU function

You'll be able to make the phone functions work, and connect a Bluetooth phone.
You won't have Emergency Buttons Assist because the Euro loom doesn't support it.
If you use a USA Eject Box, you must change the Eject Box connector from Euro type to USA Type

Here we go:

BITII Siemens Cordless Handset Euro Function USA TCU-Everest Pin, USA Function
1 red TELON, Telephone On, to Euro Eject Box X4039 p11 TCU p9, RXCAUDIO, to USA Eject Box X4545 p15
2 white DIN, to Euro Eject Box X4039 p6 TCU p11, TXAUDIO; to USA Eject Box X4545 p11
9 clear Shield, diagnostic conn to nav Not used, insulate and tie back
10 white RXD, diagnostic conn to nav Not used, insulate and tie back
11 gray TXD, diagnostic conn to nav Not used, insulate and tie back
12 purple white striped Voltage supply terminal R, to X400 p2 TCU p35, TermR (ign power), to X400 p2
13 white gray striped yellow rings* I-bus databus, to X400 p4 TCU p15, Ibus, to X400 p4
17 blk brown striped TELNF-, telephone audio out, -ve, to X400 p9 TCU p38, TELNF-, to X400p9
18 blk white stripe TELNF+, telephone audio out, +ve, to X400 p10 TCU p37, TELNF+, to X400 p10
19 red 12V, to Euro Eject Box X4039 p5 TCU p32, Charger, to USA Eject Box X4545 p1
20 blk RES, to Euro Eject box X4039 p10 TCU p4, AUDIOGND, to USA Eject Box X4545 p4
24 brown blk stripe Ground (main ground connection), to X400 p7 Not used, Insulate and tie back
25 red yellow Permanent power fm F74 10A, to X400 p1 TCU p17, Permanent power vm F74, to X400p1
28 black CTS, diagnostic conn to nav Not used, insulate and tie back
29 white brown or orange TELM, Telephone mute, to X400 p8 TCU p51, TELM, to X400 p8
31 red yellow Permanent power fm F74 10A, to X400 p1 TCU p18, Permanent power vm F74, to X400 p1
32 red yellow Permanent power fm F74 10A, to X400 p1 Warning! Permanent +12V! Not used, Insulate and tie back
33 brown black Ground (main ground connection), to X400 p7 TCU p36, Ground, to X400 p7
34 brown black Ground (main ground connection), to X400 p7 TCU p54, Ground, to X400 p7
37 yellow IN, to Euro Eject Box X4039 p12 TCU p30, RXD, to USA Eject box X4545 p18
38 green DOUT, to Euro Eject Box X4039 p14 TCU p29, TXD, to USA Eject box X4545 p9
39 clear Shield of Euro Eject Box cable, to Eject Box X4039 p7 TCU p39, Eject Box Ground, to USA Eject Box X4545 p7
42 brown blk Ground (main ground connection), to X400 p7 Not used, Insulate and tie back
43 red yel Permanent power fm F74 10A, to X400 p1 Warning! Permanent +12V! Not used, Insulate and tie back
46 red RTS, diagnostic conn to nav Not used, insulate and tie back
47 green white TELON, Telephone On, to X400 p11 TCU p33, TELON
48 blue white WDCT_OFF, to Euro Eject Box X4039 p4 Not used in USA Eject Box, insulate and tie back
52 brown white FS_MIC-, microphone -ve, to mic plug p3 TCU p19, FS_MIC-
53 clear Microphone cable shield, to mic plug p2 TCU p21, Mic shield
54 white FS_MIC+, microphone +ve, to mic plug p1 TCU p1, FS_MIC+

NOTE:
Power p25, 31, 32, 43 are all joined together in the loom
Ground p24, 33, 34, 42 are all joined together in the loom

There is no cabling for ASSIST.
The Emergency button + LED cannot be used.

If you have the Telephone Compensator installed, then you need to connect it's TELON to X400 p11, as there is no extra TELON wire in the Euro loom

The Euro loom has no cabling for illumination (58g from X400 p5), so if fitting the USA Eject box, the illumination will not work
I have described the Eject box wiring in a way that will be compatible, but you will need to change the Eject Box plug as well from Euro to USA standard
The Eject Box plug may be different in the US.


If you PM me your email address, I'll email the above as a spreadsheet