NOTICE DATE: September 14, 2009

NOTICE TYPE: M-C091409-01 Maintenance Outage – NMMS

SHORT DESCRIPTION: Scheduled Maintenance Outage of the Network Model Management System (NMMS)

INTENDED AUDIENCE: TDSPs / TSPs

DAY AFFECTED: Monday, September 14, 2009, 7:30 PM – 8:30 PM

LONG DESCRIPTION: The Network Model Management System (NMMS) will undergo an outage from 7:30 PM until 8:30 PM tonight, Monday, September 14, 2009. The Network Model Management System, currently supporting the Single Entry Model, may be inaccessible due to the rebooting of Citrix servers and may cause connection issues for anyone logged into the NMMS application prior to the reboot. The outage is expected to be less than one hour.

A subsequent notice will be sent if the maintenance period, for unforeseen reasons, exceeds the communicated end time.

CONTACT: If you have any questions, please forward them to [log in to unmask] or contact your ERCOT Account Manager. You may also call the general ERCOT Client Services phone number at (512) 248-3900 or contact ERCOT Client Services via email at [log in to unmask].

If you are receiving e-mail from an ERCOT distribution list that you no longer wish to receive, please follow this link in order to unsubscribe from this list: http://lists.ercot.com.