[U-Boot] multiple serial

[Ran Shalit]

Hello,
I am trying to undertsnad the multiple serial configuration/usage in u-boot.
in doc<http://git.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=tree;f=doc;hb=42d44f631c4e8e5359775bdc098f2fffde4e5c05>/
README.serial_multi<http://git.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=blob_plain;f=doc/README.serial_multi;hb=42d44f631c4e8e5359775bdc098f2fffde4e5c05>
it
is said:
"
* 1* The support for multiple serial interfaces as implemented is mainly
2<http://git.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=blob;f=doc/README.serial_multi;h=ad61d4261b66a00564c741db0176ca51ecece408;hb=42d44f631c4e8e5359775bdc098f2fffde4e5c05#l2>intended
to allow for modem dial-in / dial-out while still being able
3<http://git.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=blob;f=doc/README.serial_multi;h=ad61d4261b66a00564c741db0176ca51ecece408;hb=42d44f631c4e8e5359775bdc098f2fffde4e5c05#l3>to
use a serial console on a (different) serial port.
"
I am not sure I undertand what is ment in the
words "modem dial-in / dial-out".
What is actually the benefit of using multiple serial (#define
CONFIG_MULTI_SERIAL) instead of using direcet call to ns15669 driver (for
the UART'S which are not the console).
If we have a case where there is only one same UART which is the console, is
there any benefit of multiple serial ?

Best Regards,

Ran