Setup and Features
Setting up for the TEW-680MB is the same as for the 687GA. I got a successful WPA2/AES-secured connection by doing a WPS pushbutton session with the TRENDnet TEW-692GR I used as the 680MB's test partner.
Alternatively, you can connect a client to one of the 680MB's Ethernet ports, set it to a 192.168.10.XXX address and reach the bridge at its factory-default 192.168.10.110 IP. Entering http://TEW-680MB.trendnet into the browser of a computer directly-connected to the 680MB will also work.
Once you log in, you'll get the status screen shown in Figure 5.
Figure 5: TRENDnet TEW-680MB status screen
As with the 692GA, if you plan to try for 450 Mbps links, you'll need to change the Channel Bandwidth setting on the 680MB, as well as your three-stream router, from its 20 MHz bandwidth default to 40 MHz mode (or Auto 20/40). You can actually leave 20/40 mode set in the bridge, since it will adapt to whatever the router is set to.
Figure 6 shows the "advanced" wireless settings, which are really the only ones. I've exposed the dropdown menu to show the available modes (a/b/g/n mixed is the default), which curiously don't include 5 GHz 802.11n only. The HT Mode options hidden by the dropdown are Mixed Mode (default) and Green Field.
Figure 6: TRENDnet TEW-680MB Advanced Wireless settingsThe MCS setting lets you limit the maximum link rate used if you want to muck with that for some reason. But you'll need the MCS table in the 692GA review to translate MCS to Mbps. The defaults work just fine, so I'd just leave this setting alone.
As with the 692GA, there is no ability to adjust transmit power. But if you upgrade to the latest 188.8.131.52 firmware, you can see the up and down link rates (check Figure 5 above). There is still no way, however, to check the Ethernet link rates.
TRENDnet has been kind enough to provide an online emulator, so you can check out the full admin interface there.
Wireless Performance - 2.4 GHz
For testing, I used an approach similar to that used to test the TEW-687GA. The 687GA was paired with a TRENDnet TEW-691GR router, which supports 2.4 GHz three-stream N only. For the 680MB's testing, I used a TRENDnet TEW-692GR, which supports three-stream N in both bands. The 680MB was upgraded to 184.108.40.206 firmware and the 692GR was flashed with 220.127.116.11 firmware.
I changed the 680MB's Channel Bandwidth setting from its default of 20 MHz to 20/40 and used the Channel Bandwidth settings in the router to set the 20 MHz and 40 MHz modes as needed. I used WPA2/AES encryption for all tests. As is our practice, 2.4 GHz tests used Channel 1 and 5 GHz tests used Channel 36.
When running some initial tests, I noticed that throughput was significantly affected by the position of the adapter. In Location A, throughput peaked when the side of the adapter was pointed toward the router. But in Location F, pointing the front of the adapter toward the router location seemed to achieve better results. I used the position that yielded the best results.
Figure 7 summarizes 2.4 GHz results for the two TRENDnet adapters. Note that since they were tested with different routers, the results are not apples-to-apples comparable. But the numbers are interesting nonetheless.
It's normally very hard to get results > 100 Mbps using a single test stream when testing three-stream N routers with my standard test client, an Intel Centrino Ultimate-N 6300 card in a Lenovo x220i notebook. But the table below shows three out of four Location A tests came in well over 100 Mbps for single test streams.
Figure 7: Wireless Performance Table - 2.4 GHz
Best case was 175 Mbps running downlink in 40 MHz bandwidth mode. Running simultaneous up/downlink tests yielded 105 Mbps total bandwidth in 20 MHz mode and a whopping 199 Mbps in 40 MHz mode. I think this is the highest I've ever measured for the simultaneous up/down test with three-stream products. To see if I could squeeze out any more throughput, I ran a test with two up/down pairs in 40 MHz mode (four streams total) and got 232 Mbps total throughput! Another new high in my three stream N testing.
Figure 8 shows a composite IxChariot aggregate plot for all 2.4 GHz band downlink tests using 20 MHz channel width. Throughput is generally well-behaved in this plot. But you can see it takes a second or so at the start of the run for throughput to ramp up in some tests. And note the throughput decline during the Location A test. I saw both affects frequently during testing. If you browse through the other plots you'll also see higher throughput variation at lower signal levels in some of the plots.
Figure 8: TRENDnet TEW-692GR router with TRENDnet TEW-680MB client - 2.4 GHz, 20 MHz mode
I'll also note that when I switched to 40 MHz bandwidth mode, the Location F connection got pretty iffy. I had to reconnect multiple times and futz with antenna position to maintain a connection long enough to run the test. I saw similar behavior when testing 40 MHz mode with the 691GR/687GA combo.
Here are links to the other 2.4 GHz IxChariot wireless test plots for your perusal, including the four-at-a-time test: