Feed aggregator

MACOM Technology Solutions Inc of Lowell, MA, USA (which designs and makes RF, microwave, analog and mixed-signal and optical semiconductor technologies) has assumed full operational control of the wafer fabrication facility in Research Triangle Park, NC, that it purchased from Wolfspeed Inc of Durham, NC, USA in December 2023...

Luminus Devices Inc of Sunnyvale, CA, USA — which designs and makes LEDs and solid-state technology (SST) light sources for illumination markets — has added to its MP-5050 Series of high-power LEDs with the new MP-5050-240P and MP-5050-810P models, which deliver what is claimed to be industry-leading efficiency and reliability, designed specifically for demanding outdoor and commercial lighting applications...

There have been numerous circuits published in EDN as design ideas (DI) for the past few months, centering around the “Flip ON Flop OFF” circuit originally published by Stephen Woodward. These are all designed for DC voltages less than 15 V, since this is the maximum power supply voltage of the CMOS ICs that were used in their design.

Wow the engineering world with your unique design: Design Ideas Submission Guide

There are several applications that use 48 VDC as the supply voltage, such as telecom equipment, solar panel controllers, and EV controllers. In general, DC on/off switches are bulky, as there is no current zero-breaking concept as in the case of AC circuits. A DC on/off switch will break the full load current, leading to arcing and contact erosion. Because of this, bulk-sized switches with higher current capacity are employed.

Figure 1’s circuit can flip on and flop off 48 VDC with a tiny push button. D1 is a 5.6-V Zener diode. It is connected to the base of the Q2 transistor. Its emitter voltage becomes around 5 VDC (Vz-Vbe).

ICs U1 and U2 operate with this 5 VDC voltage. When the pushbutton (PB) is pushed once momentarily, a small pulse is generated, which is counted by U1. Its LSB pin becomes HIGH, which is applied to the gate of Q1. Hence, it conducts, and the output gets 48 VDC. For the next push of PB, the LSB pin of U1 goes LOW, and the gate of Q1 becomes LOW, and Q1 stops conducting. This makes the output voltage go to zero. This action repeats for every push.

Figure 1 The flip on, flop off circuit for 48 V. The output gets 48V DC when you push PB once momentarily. For the next push, output becomes 0 V. U1 and U2 operate at 5VDC only. Connect the Vcc pins of U1 and U2 to VDD and the ground pins to VSS, as shown in the above circuit. Use heat sink for Q1 for higher currents.

Since PB encounters current around a milliamp, the low current, sleek PB is sufficient to switch ON or OFF the 48-V supply with high current. With a proper heatsink on Q1, this circuit can switch ON or OFF DC currents up to several amps as per the data sheet of Q1.

Both R1 and C1 are for PB switch debounce. Both R2 and C2 are for the power-on reset of U1.

If galvanic isolation is needed (this may not always be the case), you may connect an ON/OFF switch prior to the input. In this topology, on-load switching is taken care of by the PB-operated circuit, and the ON/OFF switch switches zero current only, so it does not need to be bulky. You can select a switch that passes the required load current. While switching ON, first close the ON/OFF switch and then operate PB to connect. While switching OFF, first push PB to disconnect and operate the ON/OFF switch.

Jayapal Ramalingam has over three decades of experience in designing electronics systems for power & process industries and is presently a freelance automation consultant.

Related Content

• Flip ON flop OFF
• Latching D-type CMOS power switch: A “Flip ON Flop OFF” alternative
• Flip ON flop OFF without a flip/flop
• Another simple flip ON flop OFF circuit
• Elaborations of yet another Flip-On Flop-Off circuit

The post Flip ON Flop OFF for 48-VDC systems appeared first on EDN.

The Keysight N9048B PXE EMI test receiver, paired with a standalone stream processing unit (SPU), delivers real-time, gapless 1-GHz time domain scan (TDS) bandwidth. With the SPU upgrade, the receiver covers 30 MHz to 1 GHz in a single step—down from three in the previous version—tripling EMI test speed. Together, the units enable faster, more accurate EMI testing.

With 1-GHz FFT bandwidth, the system accelerates EMI scans by covering the CISPR C and D bands in a single pass and supports user-selectable resolution bandwidths of 9 kHz, 120 kHz, and 1 MHz. Real-time, gapless capture ensures no transient events are missed, while high sensitivity and wide dynamic range reveal signals close to the noise floor.

The test setup shortens troubleshooting time from hours to minutes and fully complies with CISPR 16-1-1:2019 requirements. Additionally, the standalone SPU provides a path for future upgrades, offering long-term flexibility.

The Keysight N9048B PXE EMI receiver will be showcased at Techno-Frontier 2025 in Tokyo at the TOYO booth. Learn more about the N9048BSPU stream processing unit by viewing the flyer here.

N9048B PXE product page

Keysight Technologies 

The post 1-GHz TDS upgrade triples EMI test speed appeared first on EDN.

Quectel’s KCMA32S Zigbee/BLE module combines a compact design with versatile connectivity for a wide range of IoT devices. It is built on Silicon Labs’ ultra-low-power EFR32MG21 wireless SoC, which integrates an Arm Cortex-M33 processor running at up to 80 MHz and supports Zigbee 3.0 and BLE 5.3 for concurrent protocol operation.

The KCMA32S enables mesh networking over Zigbee and BLE, supporting scalable, many-to-many communication for smart lighting, building automation, and home networks. An optional Secure Vault feature adds advanced security, while flexible memory configurations—up to 96 KB of SRAM and 1024 KB of flash—offer ample headroom for application development.

With its small-scale 20×12×2.2-mm LCC+LGA form factor, the KCMA32S helps reduce both size and cost in end products. It offers up to 20 GPIOs, multiplexable via the QuecOpen SDK for interfaces such as I²C, UART, SPI, and I²S. The module delivers a receive sensitivity of –104 dBm and transmit power up to +20 dBm, with optional PCB antenna, RF coaxial connector, or pin antenna interfaces.

A timeline for availability of the KCMA32S Zigbee/BLE module was not provided at the time of this announcement.

KCMA32S product page

Quectel Wireless Solutions 

The post Zigbee/BLE module enables scalable IoT networking appeared first on EDN.

Sequans’ Iris SQN9506 wideband RF transceiver covers 220 MHz to 7.125 GHz with up to 200 MHz of instantaneous bandwidth. Designed for software-defined radio (SDR) in defense, aerospace, drones, V2X, routers, and other 5G systems, it provides 20 receive and 4 transmit paths, supporting up to 4×4 MIMO in both Tx and Rx modes.

The SQN9506’s integrated RF architecture includes 10 RF synthesizers for concurrent scanning and observation. Unlimited frequency hopping with fast switching enables robust anti-jamming performance, allowing real-time hopping across channels during transmission and reception. The transceiver also supports digital interfaces such as DigRFv4 and JESD204C for both data and control.

Easily integrated with any FPGA processor, the single-die device offers low power consumption—drawing just 0.2 mA in sleep mode, 3 mA in standby, and 8 mA when idle. It is housed in a 178-pin BGA package with dimensions of 8.4×4.8×1 mm.

A timeline for availability of the Iris SQN9506 RF transceiver was not provided at the time of this announcement.

Iris SQN9506 product page 

Sequans Communications 

The post RF transceiver enables wideband SDR systems appeared first on EDN.

Two diode controllers, the AP74502Q and AP74502HQ from Diodes, provide 80-V reverse battery polarity protection for automotive systems. They also offer load disconnect to guard against overvoltage and undervoltage conditions. Compatible with 12-V, 24-V, and emerging 48-V battery systems—including those in hybrid and electric vehicles—the devices are well-suited for ADAS, body control modules, infotainment, and exterior lighting.

The AEC-Q100 qualified controllers differ in peak gate source current. The AP74502Q handles 60 µA (typical), enabling smooth startup with inherent inrush current control—useful in applications where limiting surge current is critical. By comparison, the AP74502HQ withstands a higher 11-mA peak, allowing quicker MOSFET turn-on with a 1-µs typical response.

Both controllers support input voltages as low as 3.2 V for reliable operation during cold crank conditions and provide a peak gate turn-off sink current of 2.3 A for fast MOSFET switching during voltage events. With the charge pump enabled, their quiescent current is 62 µA, dropping to 1 µA when disabled, minimizing power consumption and battery drain.

Housed in SOT28 packages, the AP74502Q and AP74502HQ cost $0.27 each in 1000-unit quantities.

AP74502Q product page   

AP74502HQ product page  

Diodes

The post ICs guard automotive systems from reverse power appeared first on EDN.

Raising the bar for enterprise NVMe SSDs, Kioxia’s LC9 drive delivers 245.76 TB in both U.2 (2.5-inch) and E3.L form factors. It joins the previously announced 122.88-TB model in the U.2 (2.5-inch) and E3.S form factors, expanding the LC9 series to meet the performance and efficiency demands of generative AI—while helping replace multiple power-hungry HDDs.

LC9 drives feature a PCIe 5.0 interface, offering up to 128 GT/s via a Gen5 single x4 or dual x2 configuration. They are compliant with NVMe 2.0 and NVMe-MI 1.2c specifications and meet many of the requirements in the Open Compute Project (OCP) Datacenter NVMe SSD specification v2.5.

These high-capacity SSDs integrate multiple 8-TB devices, each built from 32 stacked dies of 2-Tb BiCS8 3D QLC NAND in a compact 154-ball package. The drives also incorporate a controller and firmware, along with features such as die failure recovery, parity protection, and power loss protection. Dual-port operation enables high availability, and data security options include SIE, SED, and planned FIPS 140-3 compliance.

The LC9 series of SSDs is now sampling to select customers.

Kioxia

The post Kioxia adds 245-TB SSD to enterprise lineup appeared first on EDN.

Couple of years ago I designed the STM32 Nucleo F303 based control boxes, for students to learn C coding on. Multiple of my designs replaced very old, outdated designs, originally made in 2001-2002. I was looking for the ways to improve it, and also, my colleague is not that willing to learn of its assembly, so I looked how to simplify it and came up with custom shield PCB for Nucleo, routing around the pins I will need only. Once fully assembled I think it will look better than current version. submitted by /u/Peekabrrrrrr34 [link] [comments]

Choosing the right mouse can truly transform one’s working, gaming, or creative process. Be it accurate gaming or simple productivity, a dependable mouse increases lure editing speed, comfort, and efficiency. Here is a detailed look at the top ten mouse brands in the U.S, including their salient features, flagship models, and unique technology.

1. Logitech

Logitech, headquartered in Newark, California, can probably be considered the industry leader in both productivity and gaming mice. The company focuses on ergonomic office designs and high-performance gaming equipment. Popularly, the MX Master 3S is used by professionals, while gamers prefer the ultra-light G Pro X Superlight. Technologies present in Logitech include the HERO sensor, the Logi Bolt wireless connection, and the MagSpeed scroll wheel, all of which ensure pinpoint accuracy and speed, with an easy transition from work to play.

2. Razer

Razer is a household name among the laymen in the games. The company has set up shop in designing outright high-DPI, ultra-responsive competitive gaming mice for esports and competitive use. With features like Focus Pro 30K Optical Sensor and HyperSpeed Wireless technology, popular models like the DeathAdder V3 Pro and Basilisk V3 provide professional-level gaming with lightning-fast performance and haptic accuracy.

3. Corsair

Located in Fremont, California, Corsair is the very first company in this space to manufacture gaming mice that combine pure performance with extreme levels of customization. Its best-sellers include the Dark Core RGB Pro and M65 RGB Ultra, both incorporating Slipstream Wireless technology and optical switches. Corsair also provides its customers with the iCUE software with which they can alter DPI, lighting, and macros for a truly immersive gaming experience.

4. SteelSeries

SteelSeries has set up shop in Chicago, Illinois, to make its mark in the e-sports and competitive gaming world. The company usually designs the ultralight and fast mice such as the Aerox 3 Wireless and Rival 5 that feature TrueMove sensor technology and Quantum 2.0 Wireless, respectively. These provide near-zero latency and waterproof designs for situations in which games are being played at breakneck speeds.

5. HP

Based in Palo Alto, California, HP produces a vast stock of budget-class, workhorse-type mice. These are great for productivity and basic office work. Popular models, such as the HP 930 Creator Wireless Mouse and HP X3000, feature multi-device Bluetooth connectivity and silent click design, making them well-suited for every day use and professional environments.

6. Microsoft

Based out of Redmond in Washington, Microsoft concentrates on business-grade and ergonomic mice running seamlessly in the Windows ecosystem. The company’s best models such as the Microsoft Arc Mouse and Surface Precision Mouse work best with their BlueTrack sensor and for a hassle-free working experience with Surface devices and Windows-based PCs.

7. Glorious

Born and raised in Dallas, Texas, Glorious is the new rising star in high-performance gaming mice. Famous for their ultra-light honeycomb designs, the brand offers the best models on the market like the Model O and Model D Wireless. Powered with the BAMF sensor and Ascended Cord to reduce drag and maximize responsiveness, they are favorites among FPS gamers.

8. ASUS ROG

Located in Fremont, California, the ROG division of ASUS will offer you high-end gaming mice where style meets its cutting-edge hardware. ROG AimPoint sensor powers several recognized ROG models, like the ROG Gladius III and Chakram X, with push-fit switch sockets to enable customizable click resistance, thus appealing to gamers who demand precision and flexibility.

9. Cooler Master

Cooler Master, based up in Chino, California, makes gaming and everyday-use mice with a focus on price-to-performance ratio. Bestsellers like the MM731 and MM720 are equipped with Ultraweave cables, PTFE feet, and RGB lighting customizable to gamers who like the idea of having something lightweight and really nice-looking for a reasonable price.

10. Dell

Dell, headquartered in Round Rock, Texas, makes reasonably durable and efficient mice for office use and home use. Because these mice, including the Dell MS7421W and Dell WM126, are known for their long battery life, multi-OS support, and plug-and-play experience, these are the ideal companions of any business amateur as well as students.

Brand Comparison:

Brand	Use Case	Key Model	Sensor Type	DPI Range	Connectivity
Logitech	Productivity & Gaming	MX Master 3S / G Pro X	HERO Sensor	Up to 25,600	Wireless/Bluetooth
Razer	Esports Gaming	DeathAdder V3 Pro	Focus Pro 30K	Up to 30,000	HyperSpeed Wireless
Corsair	Custom Gaming	M65 RGB Ultra	PixArt PAW3393	Up to 26,000	Wireless
SteelSeries	Competitive FPS	Aerox 3 Wireless	TrueMove Core	Up to 18,000	Wireless/USB-C
HP	General Office	HP 930 Creator	Optical Sensor	Up to 4,000	Bluetooth/USB
Microsoft	Business Use	Surface Precision	BlueTrack	Up to 3,200	Bluetooth/USB
Glorious	Lightweight Gaming	Model O Wireless	BAMF Sensor	Up to 19,000	Wireless/USB-C
ASUS ROG	High-End Gaming	Chakram X	ROG AimPoint	Up to 36,000	Wireless/USB
Cooler Master	Budget Gaming	MM731	PixArt PAW3370	Up to 19,000	Wireless/USB
Dell	Office Use	MS7421W	Optical Sensor	Up to 3,000	Wireless

Conclusion:

The top 10 mouse brands that U.S. can provide comprises a diverse selection for every need, be it gaming, office, or hybrid. Brands like Logitech and Razer are in the forefront with innovative, feature-laden models, while the likes of HP, Microsoft, and Dell provide tried and tested solutions for productivity.

The post Top 10 Mouse Brands in USA appeared first on ELE Times.

A grand study conducted by the Centre for Development Studies (CDS) reiterates the major talking point all through the mobile ecosystem: India had soared further into the elite international group of suppliers of mobile phones and was positioned as the third-largest exporter of mobile phones in the world, with exports worth around US $20.5 billion during the calendar year 2024.

The Meteoric Rise: From Dependent on Imports to Export-Driven Power:

Six years ago, in 2017-18, India was exporting a mere amount of US $0.2 billion worth of mobile phones. By 2024, this figure has crossed the $24 billion mark marking an astonishing almost 11,950 per cent increase. Such explosive growth coincided with India moving from being a player in domestic manufacturing only to a scale export-led manufacturing partner in the bigger global arena.

Government encouragement and production-related incentives:

Key to this change is the Production-Linked Incentive (PLI) scheme floated in 2020 and implemented ever since. Since then, this bold policy has largely helped the foreign Original Equipment Manufacturers (OEMs) and contract manufacturers to invest in local facilities and infrastructure. So, we have a big-scale output and a robust integration into global value chains (GVCs).

Multi-layered domestic value addition stood out as a strong trend. Direct value for production of mobiles has seen an almost 283% rise from US $1.2 billion in FY 2016–17 to about US $4.6 billion in FY 2019–20. Even more impressive has been the growth in indirect value addition upstream supply chains by 604%, from US $470 million in FY 2016–17 to about US $3.3 billion in FY 2019–20.

With this economic growth came a greater occasion for employment: Further estimates indicate that more than 1.7 million direct and indirect jobs were linked to mobile production in 2022–23, and the number of export-related jobs rose at an astounding 33-fold. Wages too are rising, thanks to growing high-skill jobs in export-oriented units.

Global Trade Strategic Development:

India now ranks third in the mobile phone exports after China and Vietnam, having achieved exports worth nearly US $20.5 billion in 2024. World’s Top Exports data suggests that India exported 7.1% of global mobile exports in 2024, amounting to US $20.48 billion an increase of 585% compared to 2020.

This is in consonance with the CDS findings, positing India as a major exporting hub for mobiles. Contract manufacturing for brands such as Apple, Samsung has further accelerated exports, while the competitive ecosystem consisting of the likes of Foxconn, Wistron, Pegatron, and Dixon Technologies leads to high-volume outputs.

Conclusion:

The mobile export surge in India is more than just headline numbers; it means a structural global competitiveness transformation, portraying how policy-driven incentives together with industrial ecosystems can facilitate a rapid climb. With this blueprint led by mobiles now gaining momentum, other electronics floors such as laptops, networking equipment, and consumer electronics are ready to replicate the success, taking India one step further into becoming a global manufacturing powerhouse.

Governed jointly by the Centre for Development Studies and the Indian Cellular and Electronics Association (ICEA), the report intends to provide a clearer understanding of the effect of government policies on India’s electronics manufacturing sector.

The post Study Finds India’s Mobile Exports Surge to $20.5 Billion, Ranking 3rd Globally appeared first on ELE Times.

Shipping in PCBs has become extremely ecpensive where I live unless you buy in bulk...tried my hand at etching PCBs to develop prototypes...nice to be able to do this...ofc not having multiple layers adds lots of limitations, but I can see myself testing out new chips or designing my owm modules in an afternoon... submitted by /u/Separate-Choice [link] [comments]

I built a thing. See gallery* 3KW 15-170VDC Programmable H-bridge driver. With adjustable Duty, Frequency (250Hz - 160KHz), and deadtime. ESP32 for the controller SSD1306 I2C 128x64 OLED Display 74AHCT125 Logic level converter and output control IR2110 x2 hi/lo gate drivers IRFP260N MOSFETS x4 Artic Cooling AM3 cooler from the junk drawer 15-150VDC to 12V DC-DC converter module - for gate driver ICs and active cooling 7-40VDC to 5V DC-DC converter module - for esp32, display and logic converter PWM thermo fan controller module Lots of various TVS diodes, some ferrite beads, the usual caps and resistors, and a handful of tactile buttons. As the controller is a ESP32, it can be re-flashed depending on what we are trying to blow up today. Inverting (Arcs/induction heating/Switching transformers) - Flyback (More sparks) - Half-Bridge - Motor Controller (zoomzoom) Obviously the first thing to try is big arcs with Aliexpresses finest £6 'wind yer own primary' HV transformer for about 35KV output from a 35V 10A draw. (If I tune it in just right I get u/130V peak to peak in the tank) https://www.youtube.com/shorts/37gKJzHNFdA Next was an induction heater, worked well at 90KHz and a 5 turn coil and 4uF in the tank, drawing 15 or so amps at 30V will turn bolts into LEB's... Didn't play much with the induction heater on the bench though, as the fields play havoc with anything in range. PC crashes, monitors glitch, and unconnected multimeters showing random voltages. Building the hardware was simple enough: check datasheets and assemble. I didn't make a diagram as I had a fair idea of what I wanted in my head, so I then just let my hands finish the job. The firmware is another matter. Having never played with any of these little controller chips before, or tackled any kind of coding bar a few websites, it. was. a. challenge. I found that if I were patient, the freebie chatGPT gave me a hand with bits as long as I didn't ask too many questions in a short timespan (using that was another frustrating experience in itself ha). I got there in the end though with... * Complimentary PWM output (using a synced GPIO pin for resyncs across the legs, as for some reason the ESP32 will fall out of phase occasionally when adjusting the frequency) * Full frequency control on the fly * Duty control with min/max limiter * Switching deadtime control (with frequency-related limiter) * 2 stacks of resistor ladder buttons Yet to do Polish and combine firmwares and add a mode of operation menu (argh). Add current sensing, so it can scan frequencies for the sweet spot of transferring energy. (some hardware tweaks and more arghhh) Large capacitor bank sitting at the input (as my power supply is not enjoying the huge pulse currents much) More TVS diodes when I can find some that don't come with 30 quids worth of 'handling fees' T'was fun to make, a steep learning curve to program, and great entertainment when built. Mates enjoyed the firework show with the big arcs, jacobs ladder, and the odd game of 'how short a rollie can I light off the arc' , while I enjoyed getting some rusty as shit bolts undone, and watching people with short rollies fall out of seats. All in all, it cost me about £40 or thereabouts. 10/10 - would make again. *Bonus photos include late night shed visitors submitted by /u/RollingWithTheTimes [link] [comments]

The new demonstrator offers a complete hardware development solution with a GaN power stage for three-phase, radiation-exposed motor drive systems.

Візит делегації Японського агентства міжнародного співробітництва kpi чт, 07/24/2025 - 22:49

NUBURU Inc of Centennial, CO, USA — which was founded in 2015 and developed and previously manufactured high-power industrial blue lasers — says that NYSE American LLC has accepted its plan to regain compliance with continued listing standards, granting an extension through 29 October 2026...

Honestly... What is wrong with people?!? My first thought: oh well the pictures text is probably in german or something. But once you realize you can't unsee it. I can understand opinion content being written with AI, gosh, I wouldn't even mind if co-workers sprinkled AI on their emails, but dude, safety stuff? My goodness... https://pidora.ca/safe-gpio-power-methods-that-wont-fry-your-raspberry-pi/ submitted by /u/ferminolaiz [link] [comments]

Intelligent power and sensing technology firm onsemi of Scottsdale, AZ, USA has expanded its existing multi-year collaboration with Germany-based motion technology company Schaeffler (formerly Vitesco Technologies) through a new design win that leverages onsemi’s next-generation EliteSiC product line of silicon carbide MOSFETs. The onsemi solution will power the Schaeffler traction inverter for a leading global automaker’s plug-in hybrid electric vehicle (PHEV) platform...

Early in my engineering career, I worked with a couple of colleagues on an outside project. We had a concept for a security system for gaming arcades. At the time, arcades were very popular, hosting games like Pac-Man, Space Invaders, and Pinball. One of the business problems, though, was the theft of coins from the gaming machines. Apparently, when staff members were emptying the coin boxes, they would pocket a handful of coins. Theft in these arcades was said to be around 25%.

Do you have a memorable experience solving an engineering problem at work or in your spare time? Tell us your Tale

Our concept for preventing these thefts was a device that consisted of two parts. One micro-based device was installed in each of the arcade games. This counted the coins as they entered the slot. Then, periodically, the total coin count and game ID were transmitted, via the power line, to the back office. In the back office was the receiver. It monitored the power line and collected all the transmissions from the various games. This back-office device was also connected to a telephone landline, and once a day, the central office would call into the back-office device to have the daily data sent to it. The hand count of coins could then be reconciled with the electronic coin count from all the machines.

My colleagues and I divided up the work, with one doing the schematic and PCB prototypes. Another did the enclosures, labeling, etc. I did the firmware for the two pieces of equipment. After many months of evening work, we had a system that performed just as we expected. We also got a test site identified to install a complete system. As the arcade was more than 1000 miles away, we had someone at the other end install the system. After a few days, we got a call from the arcade operator telling us the office device would not answer the phone call into it. The hardware design was rechecked to see if the opto-isolator, signaling the firmware of a high voltage on the ring line, was designed correctly to take into account lower-level ring voltages—no issue there. This issue fell on me as it appeared to be a firmware issue. I tested my firmware dozens of times with various changes using an actual landline—it always worked. After many days of testing, I announced that I could not find any issues.

As a last resort, we had the hardware engineer fly to the arcade site with a raft of test equipment. After only a few hours, he called and said he had found the issue. The standard for ringing for a landline is defined by ANSI T1.401-1988 section 5.4.2, which I followed for the firmware. According to this standard, the ring cadence consists of 2 seconds of ringing followed by 4 seconds of silence. The phone system, in the town where the arcade was, followed this…sort of. During the ring, there was a short dropout ( about 80 ms, if I remember correctly). So, what the firmware saw was about 1 second of ring, no ring for 80 ms, then 920 ms of ring, and then 4 seconds of silence. The firmware, noting that the ring was only one second long, determined that it wasn’t a valid ring and therefore wouldn’t answer. The discovery of the issue was long, difficult, and expensive. The fix was easy to implement in firmware. After updating the firmware, the arcade system worked very well (we never got rich off it, though…another, non-technical, story).

The takeaway here is not how to construct landline phone answering firmware; those days are long gone. But the lesson here is that when you have an issue, suspect everything. We continued to have discussions on why the system would not answer the phone when we knew it was sensing the ring. We never thought that maybe the cadence, defined by an ANSI standard, would not be correct. Why the town’s telephone ring system had an 80 ms gap was never discovered, but it obviously didn’t meet the spec. So, if you can’t find a problem in your device, maybe it’s the other device(s) you’re connecting to. And at that point, the other system needs to be checked against its specs.

Damian Bonicatto is a consulting engineer with decades of experience in embedded hardware, firmware, and system design. He holds over 30 patents.

Phoenix Bonicatto is a freelance writer.

Related Content

• PUT a reset in its place
• Adaptive resolution for ADCs
• A beginner’s guide to power of IQ data and beauty of negative frequencies – Part 1
• Obtaining a patent in a corporate environment

The post When a ring isn’t really a ring appeared first on EDN.