Tag: electronics

Fixing a dead 40Gbps Celestica D2060 network switch

I have had a dead Celestica D2060 network switch laying in my garage for a while and decided to finally attempt to fix it. D2060 is a Broadcom Trident2 BCM56854A2 powered device offering 48x10G SFP+ and 6x40G QSFP+ ports, with an Intel Atom Rangeley C2558 based control plane – notorious for dying due to a CPU bug.

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Controlling a SIM800L modem

My quick notes regarding a SIM800L module on an inexpensive SIM800L EVB “SIM800LV2.2” carrier board from eBay. Communicates happily with a computer through a generic USB<>TTL converter, 5V logic levels and 5V power at 9600 baud. Carrier board includes a TTL level shifter and 2 diodes in series to drop the voltage from 5V to ~3.6V.

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