Phone records show that Martin's inbound phone call from Witness #8 occurred at 19:12 which was during Zimmerman's dispatcher call.
http://media.nbcbayarea.com/documents/call+log.pdf
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That is when the call ended, he had already been on the phone for 18 minutes
No, that's when the call was received, if you look in the right column you can see the duration was 4-minutes. That means the inbound call was received during Zimmerman's dispatcher call.
- Dispatcher Call Starts approximately 19
00 (0 minutes, 0 seconds or 0
from inside his truck,
- Zimmerman says Martin is coming toward the truck at approximately (19:12:00, 01:00),
- Zimmerman says Martin has his hand in his waistband (19:12:05, 01:05) as the same time as phone records show an INBOUND call from the girlfriend at (19:12),
- Zimmerman says he has something in his hand (19:12:26, 01:26), which may be Martin's cell phone (Good for Zimmerman),
- Zimmerman make note that Martin has turned to run (19:13:09, 02:09),
- Zimmerman exists the vehicle, you can hear the truck door opening and closing about 3 seconds later (19:13:11, 02:11),
- You can hear wind noises now as Zimmerman begins following Martin and dispatcher asked Zimmerman if he was following him (19:13:14, 02:14),
- You can hear Zimmerman acknowledges with "OK" that he heard the dispatcher say he didn't need to follow Martin (19:13:24, 02:24),
- No other position information can be determined from the phone call which ended at approximately 19:15:11, 04:11).
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That is when the call ended with his girlfriend. He was already on the phone with her before he went to the C store. They placed her phone call starting at 6:54 and lasting 18 minutes until 7:12. This is something I have already posted with a link.