During the replacement of the networking onboard nb Tanya Louise with gigabit, the main 8-port distribution switch was also changed. Here’s a quick teardown of the old one.
This has been quite a reliable switch for the internal networking on board, but the time has come to switch over to something a little faster. This switch will be getting repurposed for the slower devices on my network, such as the radiation monitor & the raspberry Pi systems.
Here’s the top removed from the switch. It’s a very simple construction, with a small power supply section & the main switch IC in the centre.
All the magic happens in this main IC, a Realtek RTL8309SB Fast Ethernet switch. This is a feature-packed IC, with support for VLAN tagging, but being in a small unmanaged switch the extra features aren’t used.
Main power supply is provided by a jelly bean MC34063 DC-DC converter, and an adjustable LM1117 linear regulator. Nothing much special here.
The only other parts are the magnetics for the ethernet interfaces, behind the ports themselves.
Since the boat was still running it’s internal network on 10/100M speeds, an upgrade was decided on, the internal WiFi signal strength was also pretty poor further than a few feet from the NOC.
The new router is a Cisco/Linksys AC1750 model, with gigabit networking, and full 802.11ac 2.4/5GHz Wireless. This router also has a built in media server, print server, USB3 & USB2.
Teardown time! Here’s the router with the cover removed. Most of the fun stuff is hidden under the shields, but these aren’t fully soldered down & the covers are removable. The 6 antennas can be seen spaced around the edge of the housing, the main CPU is under the large heatsink upper centre. The radio power amplifier stages are underneath the shields, while the main RF transceivers are just outside the shields.
Wireless N is provided by a Broadcom BCM4331, this provides full dual-band 3×3 802.11n support. Being 3×3 it is actually 3 separate transceivers in a single package, to get much higher throughput rates of 600Mbit/s.
Wireless AC is provided by it’s sister IC, the BCM4360, with throughput speeds of 1.3Gbit/s. Both of these transceiver ICs connect back to the main CPU via PCI Express.
To get increased range, there are a trio of Skyworks SE5003L +23dBm 5GHz power amplifier ICs under the shield, along with the TX/RX switching & antenna matching networks. Heatsinking for these is provided by a sink screwed to the bottom side of the PCB. The outputs to the antennas can be seen at the top of the image.
The 2.4GHz section is fitted with a trio of Skyworks SE2605L +23dBm 2.4GHz power amplifiers, with a similar heatsink arrangement under the board. Unlike the 5GHz section, the 2.4GHz antenna feeds are soldered to the PCB here instead of using connectors.
The main CPU is a BCM4708 Communications Processor from Broadcom, as for the other Broadcom chips in this router, very little information is available unless under NDA, but I do know it’s a dual core ARM Cortex A9 running at 1GHz, with built in 5-port gigabit ethernet switch.
Working RAM for the processor is a Hynix H5TQ2G63DFA 256MB part.
More to come on the installation of the new networking, with it’s associated 4G mobile gateway connection system.