--- a/FCDEV3B-repackaging	Wed Oct 10 16:33:11 2018 +0000
+++ b/FCDEV3B-repackaging	Wed Oct 10 17:22:57 2018 +0000
@@ -181,3 +181,50 @@
 The above approach would provide a usable digital voice interface that would be
 completely transparent (invisible) to the Calypso DSP and even to the ARM-side
 firmware, hence it should work without any nasty surprises.
+
+Triband vs. quadband
+====================
+
+One shortcoming of our current FreeCalypso modem solution is that it is triband
+and not quadband; more specifically our standard hw build omits the GSM850 band,
+or we can build a different configuration that supports GSM850 but omits EGSM
+(the 900 MHz band).  To the best of our knowledge the GSM850 band is used very
+little these days, but being only triband makes us look bad compared to the
+competition: all of the mainstream proprietary GSM modem modules are fully
+quadband these days.
+
+It *is* possible to make a Calypso-based quadband modem, as TI had one: their
+Leonardo reference board for the Calypso+Iota+Rita chipset existed in several
+versions some of which were quadband, and their E-Sample board (Calypso+) which
+used the same Rita RF block was also quadband.  However, changing our current
+FC modem design from triband to quadband would involve a highly invasive PCB
+layout change: basically our entire modem PCB layout and particularly the GHz RF
+section would have to be ripped up and reshuffled into a different arrangement.
+Furthermore, if we as the FreeCalypso community do decide that we wish to
+produce a quadband modem, I (Mother Mychaela) would NOT be comfortable with
+entrusting the needed re-layout work to an "ordinary" PCB layout contractor who
+is not a cellphone RF design expert, instead we would need to get a consultation
+from an RF PCB design expert who has experience very specifically with GSM
+cellphone design and not any other applications.  Finding such an expert would
+be a major task in itself, and that expert most certainly won't come cheap.
+Therefore, a quadband FreeCalypso modem probably won't happen unless we get
+someone with a lot of money to throw around.
+
+There is one exception, though: if anyone would like to see our FreeCalypso
+modem repackaged into the SMT module form factor copied from BenQ M32 and pays
+for that venture, the result would be naturally quadband as the layout of BenQ's
+module follows the same floorplan in the RF section as TI's quadband Leonardo
+and E-Sample layout.  However, that approach would involve a step to reverse-
+engineer BenQ's layout by slicing their board and imaging its inner layers,
+hence anyone seeking this approach would need to be prepared to pay for that
+step.
+
+If anyone ever does pay for the creation of a quadband version of our
+FreeCalypso modem solution, be it in BenQ's physical form factor or some other,
+this quadband modem will need a different firmware build configuration: there
+is no way to have the same fw image work on both triband and quadband modems
+given that the RFFE control signals are different, and there would be no way for
+the fw to autodetect which hw it is running on.  But all of the other design
+guidelines listed above should still be followed, so we can have only two fw
+build configurations (triband and quadband) without an explosion of further
+build variants for different GPIO wiring and whatnot.