A group of companies came together to find an innovative solution for recycling phone parts, demonstrating how reusing electronics can have a positive impact on sustainability.
(Image: Deutsche Telekom)
Electronic waste, especially discarded cell phones, poses a significant environmental challenge. The disposal of these devices contributes to the accumulation of metal, plastic, and functional semiconductors in landfills. While materials like gold from PCB fingers can be salvaged and repurposed, the idea of giving working semiconductors a second life intrigued engineers from companies like Deutsche Telekom, Infineon, Fairphone, MaxLinear, Sagemcom, and Citronics. Their collaborative efforts resulted in a prototype DSL router that incorporates 70% reused parts from old cell phones and telecom network routers.
To delve deeper into the construction of the router, I had the opportunity to interview Henning Never from Deutsche Telekom and Julian Haslberger from Infineon.
Why Choose a DSL Router?
Deutsche Telekom, being both a mobile carrier and a fixed-line communications provider, markets its own fixed-line user equipment, including routers. “We are committed to enhancing the sustainability of our hardware,” explained Never. “We began by focusing on eco-friendly packaging, shifting away from single-use plastic to cardboard.”
Unsatisfied with merely eliminating single-use plastic, the engineers at DT recognized the impending fate of phones, in-home user equipment, and telecom networking gear ending up in landfills. Their objective was to find a means to repurpose semiconductors, connectors, and other components.
Figure 1. A Fairphone 2 served as the primary parts contributor for the DSL router project. (Image: Fairphone)
To explore the realm of electronic component reuse, DT engineers reached out to various companies and institutions, culminating in the formation of a consortium that included Dutch smartphone manufacturer Fairphone, semiconductor giant Infineon, and contract manufacturer Citronics — a company with previous experience in repurposing Fairphone 2 parts. The outcome was a DSL router crafted from old cellphone components.
The development of the proof-of-concept DSL router stemmed from the simplicity of its electronics, as Never pointed out, “It’s not an intricate electronic device.” He further explained, “We are a major provider of routers in Europe under the ‘T’ brand logo. Hence, we opted to create a router.” Never highlighted the prevalent use of DSL and VDSL for fixed connections in Germany.
The prototype leverages parts from a Fairphone 2 (Figure 1), known for its easily detachable and replaceable components such as the camera and battery. Fairphone’s emphasis on reusability and recycling of parts and materials made it an ideal choice. The modular design of the phone (Figure 2) enabled engineers to utilize the phone’s PCB assemblies without the need to desolder ICs. Few connectors had to be removed to accommodate the router’s casing.
Figure 2. The Fairphone 2’s modular design lets engineers use the phone’s semiconductors without removing them from the PCBs. (Image: Deutsche Telekom)
“This was the rationale behind selecting the Fairphone 2,” Never emphasized. “It may not match the performance standards of current devices, but due to technological limitations, we refrained from attempting to build a high-end 1 gig optical router. Our aim was to showcase a proof-of-concept capable of fulfilling basic tasks without excessive complexity.”
The prototype DSL router functions over existing copper lines. Never highlighted the enhancement of many copper lines in Germany, shifting the active systems like DSLAMs closer to users, resulting in speed boosts enabling VDSL speeds up to 250 Mb/sec. However, this upgrade led to increased heat generation in network equipment, necessitating innovative cooling solutions.
Utilization of Reused Parts
The engineers repurposed the phone’s main board containing the CPU and memory. They integrated a USB port for connecting the router to a host computer for firmware updates and diagnostics. Connectors from an old telephone router were incorporated to physically link the unit to the network. A DSL modem IC from a previous router facilitated the connection of the prototype router’s signals to the network. The internal firmware of the prototype operates on Linux.
Given the phone’s existing Wi-Fi capabilities, engineers enabled it to connect to user equipment. The router employs a single antenna compared to the multiple antennas found in modern routers. Its cellular connectivity stems from the phone’s components, allowing connection to the cellular 4G network. Never clarified that although the router supports cellular connectivity, this feature wasn’t tested in the prototype.
Home routers providing wired internet access typically feature Ethernet ports. In this project, engineers utilized an Ethernet interface chip (VDSL chip) from a decade-old DSL modem to link with the Fairphone mainboard. “Initially, we planned to desolder and reuse a VDSL chip from an old Deutsche Telekom branded router. However, we discovered that the chip was designed to function exclusively with the corresponding CPU, which would have excluded the Fairphone CPU from the project,” Never elaborated. “This realization emphasized the importance of addressing proprietary chipset designs when working with old electronics. It was a valuable lesson for us.”
While a significant portion of the prototype comprised reused components, a new board was designed to connect the phone’s boards to the network interface IC, the USB IC, and mount connectors for networking and power supply through an external adapter. Figure 3 illustrates the transition from a smartphone to a prototype DSL router.
Figure 3. Engineers designed a board to hold the boards from the phone and marry them with components reclaimed from a telecom network router. The final prototype appears on the right. Image courtesy of Deutsche Telekom.
“The elegance of the Fairphone stems from its modular design,” Haslberger added. “The ability to dismantle and reuse components, especially at the semiconductor level, is where Infineon and other collaborators played a crucial role.”
Infineon and other project contributors supplied used components like connectors and the DSL modem IC. After disassembling or desoldering these parts, they underwent refurbishment and testing as part of the standard validation process before integration into the prototype. The primary objective was to showcase the viability of reusing electronics at various levels and explore potential scalable projects in the future.
“We also required transistors and capacitors,” mentioned Never. “We sourced them from the old telecom router.” Additionally, two microcontrollers were essential to manage the interaction between the Fairphone and the VDSL board, both of which were reused.
Future Prospects
To transition the project to a production-ready status, engineers must establish an ecosystem due to the labor-intensive nature of the initial unit, as highlighted by Haslberger. “We need to assess the entire value chain for feasibility, which is our primary objective for this project.” Automation of the reusing process, from phone disassembly to part extraction and testing, is crucial for successful implementation.
The DSL router crafted from reused components made its debut at the Mobile World Congress in Barcelona. Post-event, engineers intend to design a board enabling easy installation of upgradeable parts as technology progresses. For instance, they aim to incorporate current and future Wi-Fi radios for enhanced bandwidth.
“We have ambitions to create more,” Never affirmed.
