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neEngineering, Inc. 505.332.2604 (voice) <br /> 505.332.2107 (FAX) <br /> P.O. Box 20490, Albuquerque, NM 87154 tline@nmia.com <br /> <br />March 18, 1997 x/L)~'r\ <br />Mr. William Adams, Superintendent ~//¢ ¢~ <br />Public Works Services Department <br />City of Redwood City <br />1400 Broadway <br />Redwood City, CA 94063 <br /> <br />RE: ENGINEERING SERVICES FOR SCADA COMMUNICATION UPGRADE <br />FEASIBILITY STUDY <br /> <br />Dear Mr. Adams, <br /> <br />Timberline Engineering, Inc. is pleased to submit this proposal for engineering services. We <br />propose to assist the City in studying the feasibility of a replacement SCADA con-a-nunication <br />system. <br /> <br />As consulting engineers, our specialty is the design of SCADA and telemetry; in fact, Timberline <br />has several projects in your area: a microwave/900 MHz MAS radio upgrade project for Contra <br />Costa Water District in Concord; a SCADA/telemetry project for the City of Modesto (we <br />converted the City's telephone telemetry to 900 MHz MAS radio); and 900 MHz spread <br />spectrum, licensed 90OMHz MAS.radio-and SCADA projects for Sacramento County. <br /> <br /> Background: <br /> <br /> The City is currently using leased Advanced Digital Network (ADN) telephone lines for <br /> telemetry to link its water, wastewater and stormwater remote sites to its SCADA master station. <br /> The high cost of these lines, coupled with poor response on trouble calls by the service provider, <br /> warrant investigation into alternative communication media to meet the City's SCADA <br /> reqnireme_n, ts. A study is needed to evaluate alternatives and develop a recommendation. This <br /> study is especially important now as the City is contemplating other SCADA system upgrades <br /> and improvements. <br /> <br /> A note about ADN: This service features synchronous digital transmission of data and is <br /> supposed to be more reliable than analog (voice grade) service but is generally more expensive. <br /> Most SCADA systems use asynchronous data transmission. This study must include an <br /> assessment of the data communication interfaces at the SCADA master station and remote site <br /> PLCs. Switching to a different communication media may require additional interface <br /> modifications. <br /> <br /> <br />