Description: This item was originally used to remotely control a "TUNE IN FOR TRAFFIC INFORMATION WHEN FLASHING" traffic advisory sign via an FM radio station's SCA. It includes a DTMF encoder board with timers. Pressing once of the light-up buttons on the front panel cause a unique tone pair to be generated for 5 seconds and be button to illuminate for the duration on the label. This corresponds to the length of time that the remotely controlled traffic sign by the highway is flashing. So, the traffic reporter would press one of the timer buttons (:30 sec through 2:30) depending on the length of the report. This sent a DTMF signal via an SCA encoder connected to the FM station transmitter to the traffic sign where it would be received, and depending on the DTMF tone received, would cause the lights to flash for a set length. The DTMF tones are generated by a UM9559E chip. Cool, eh? There is also a DTMF decoder board built-in which is similar to the one at the sign. A local SCA receiver was used to pick up the transmitted tones which were then fed back into this unit and caused the corresponding button to illuminate, confirming that the signals were sent. A security switch (key not included, unfortunately) is used to place the unit in a TEST mode that allowed the tones to be generated and decoded without triggering the sign. The DTMF tones are decoded by a 75T202 chip. An SCA high pass audio filter (BNC jacks) was used to filter out the baseband station audio and stereo pilot signals, leaving the 57 and 92 kHz SCA signals able to be cleanly received. The images in this listing show the location of the various boards and interconnections on the rear chassis which is mounted to a standard 2RU 19" rack panel. The screw terminal strips are used to connect to external triggers (closures to ground) and to light external lamps. The DTMF audio inputs and outputs are on the transformer balanced shielded pair leads. All of the circuitry is tested and functions. This listing is for the item shown in the pictures and does not include any associated equipment described for its original application, ie, SCA encoders, decoders, FM radio stations, traffic signs, traffic, highways, etc. Have questions? Let me know...
Price: 99.99 USD
Location: Greenwich, Connecticut
End Time: 2024-05-11T01:00:22.000Z
Shipping Cost: N/A USD
Product Images
Item Specifics
All returns accepted: ReturnsNotAccepted
Type: DTMF Encoder/Decoder
Brand: Unbranded
