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The TX-PUC approved a "partial" overlay of 512 back in 2001. NANPA and
the PUC announced the new "partial" overlay area code as 737, but the
implementation dates were "TBD". This is how 512/737 remained ever
737 was to overlay only certain exchange areas within 512, mostly the
main corridor between Austin and San Marcos, but the other fringes of
512 would retain seven-digit local dialing and not have any 737
numbers at the outset, but the overlay would have most likely expanded
at a later date. However, NO dates were ever determined, neither for
the initial partial overlay, nor for any later expansion to overlay
the rest of 512.
But ironically you should inquire about this now, because recently,
NeuStar-NANPA and the telephone industry drafted a petition which has
already been presented to the TX-PUC (last week in January 2010), to
re-open the 512/737 overlay, but this time, the telephone industry
wants the TX-PUC to approve a full overlay of all of 512 with 737,
along with the obvious mandatory ten-digit local dialing. This is
still pending before the TX-PUC, so there arent even any "potential"
impelementation dates at this time. The TX-PUC still has to approve
this petition by the telephone industry "thru" NANPA.
ALSO, Remember that NANPA does _NOT_ make the choice of split
vs. overlay. NANPA presents several relief options to the telephone
industry when NANPA feels that relief is needed for an area code. It
is then a consensus process by the telephone industry who attend the
in-person meetings or participate on conference calls as to the
particular choice of relief method(s) to be presented to the state
regulatory agency by NANPA. Canada has a similar process, where the
Canadian telcos meet in-person and/or by teleconference, have their
consensue process as to which relief method is destired, which is then
presented to the CRTC (regulatory) by the CNA (Canadian Numbering
Administrator). NANPA and the CNA do NOT "vote" in the consensus
process. Both are "neutral" parties which present various relief
method options for an area code. The telcos involved can even present
additional relief method options for discussion if they so choose. And
then after a vote by the telcos themselves (but NOT including any
"vote" from NANPA or the CNA), then NANPA presents the industry's
decisions as a petition before the state commission, and the CNA
presents the Canadian telcos' decisions as a petition before the CRTC.
So, in closing, 737 is a PENDING overlay (partial or complete) overlay
to 512 in the Austin/San Marcos/vicinity area in Texas, but no dates
were ever determined. And most recently, the telco industry has
requested NANPA to re-open the procedings before the TX-PUC, and this
time are requesting a review by the PUC for a "complete" or "full"
overlay of 512 with 737.