Cisco WISM EE-porn - Page 1
Forum section: electronics / general

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: December 26, 2014, 12:46:15 am
content: (Posting this a second time because my original post disappeared mid-post due to file size limits)So I'm sitting at work on an xmas day, and I noticed the network guys left out a Cisco WISM module. I guess they're replacing it, but I decided to take a gander at it to see what kind of complexity goes into such a device. I must say, I'm quite amazed at how well the thing is laid out. It's a two board construction, with lots of via stitching. One thing I did notice though, is it looks like they ran out of room in a couple spots and came up with a couple daughterboards that get soldered directly to the top PCB. There might be a lot of ASICs or FPGA's on the thing, but I still think it's a pretty nice design. Couldn't imagine how many layers the boards have, but this thing looks pretty nice. (Then again, I would hope so, considering Cisco equipment costs thousands)If you're interested, feel free to take a gander:http://imgur.com/a/MpytDAny apologies in advance for quality, as I don't have a tripod for my phone.edit: another thing I found interesting, is the RJ45 port on the rear of the top board. Once the unit is slid into the router core, that port would be inaccessible. I wonder what it's for...

author: wraper
author_rank: Unknown
timestamp: December 26, 2014, 01:14:17 am
content: Quote from: justanothercanuck on December 26, 2014, 12:46:15 amNo, they just didn't bother to design they own power circuits and used assembled modules from some supplier. BTW there are PCB transformers on the module.

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: December 26, 2014, 01:29:41 am
content: Quote from: wraper on December 26, 2014, 01:14:17 amShame really, you would think they would have designed those themselves too, seeing they're making such a big piece of equipment. Nice find, I thought those were just chokes or inductors. I had looked up FDS 7788, but all I got was that they are N-channel MOSFETs.

author: marshallh
author_rank: Unknown
timestamp: December 26, 2014, 04:39:14 am
content: I have some Motorola CMTS boards, I should post a thread about them. They're a lot like yours - brute force engineering

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: December 26, 2014, 01:33:00 pm
content: That would be interesting to see.

author: Unknown
author_rank: Unknown
timestamp: December 27, 2014, 11:18:02 pm
content: Quote from: mojo-chan on December 27, 2014, 08:04:42 pmThose features are only available in the special gold coloured 'NSA Edition' boxes. You have to purchase the extra licence yourself though ;-)

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 27, 2014, 11:40:10 pm
content: Quote from: justanothercanuck on December 26, 2014, 01:29:41 amWhy reinvent the wheel? They're in the business of making network gear, not PSUs.Also, chances are these converters have more layers and/or heavier copper than the main PCB as they use planar magnetics (PCB traces for windings)

author: retiredcaps
author_rank: Super Contributor
timestamp: December 28, 2014, 08:23:01 pm
content: Many of Cisco's over priced acquisitions become PSA until they can get fully integrated, sometimes never, into their flag ship products.PSA = Power Sucking Alien

author: TerraHertz
author_rank: Super Contributor
timestamp: December 29, 2014, 12:31:17 pm
content: Here's more Cisco 6500 option porn. A WS-F6700-DFC3B Distributed Forwarding Card.I have two of these cards, that were discarded. Since they are 'B' version, and the anti-static bag labels say 'C' version, I gather they were tossed during an upgrade, and likely work. I grabbed them just for the incredibly dense PCB layout porn, and curiosity of what are the chips under those heatsinks. Otherwise I have no use for them at all. If anyone wants one or two for $50 ea, let me know. I guess I should list them in buy/sell. Had forgotten about them till I saw this post.I'd still like to know what the chips are, but the heatsinks are glued on VERY solidly. It seems like wrenching them off would destroy the chip packages first. Ha ha... probably that's the fate in store for at least one of these boards, when my curiosity eventually overcomes my reluctance to destroy such a work of art.

author: timb
author_rank: Super Contributor
timestamp: January 01, 2015, 10:20:47 am
content: RJ45 ports are traditionally there to provide a serial console on Cisco gear for initial setup, config and upgrades.Sent from my Tablet

author: Rasz
author_rank: Super Contributor
timestamp: January 01, 2015, 10:54:14 am
content: stuff like this always reminds me ofhttp://nsa.unaligned.org/hw.phpwould be nice to have a database of cheap outdated/surplus equipment that harbours shiny fpga chips

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: January 01, 2015, 08:45:26 pm
content: Quote from: timb on January 01, 2015, 10:20:47 amOn the front maybe, but not on the back, near where the boards make connection to the router core. AFAIK, there's no way to power the board outside of the core, so having a port back there doesn't make a whole lot of sense.edit: I had another look since the board is still here... the RJ45 jack seems to be partially connected to a nearby JTAG header. What they're programming in-circuit is beyond me, but it looks like that one is sortof solved.Quote from: TerraHertz on December 29, 2014, 12:31:17 pmNice board.

author: marshallh
author_rank: Unknown
timestamp: January 02, 2015, 02:03:55 am
content: The secret is a heat gun and gentle levering pressure, works everytime

author: TerraHertz
author_rank: Super Contributor
timestamp: January 02, 2015, 06:49:44 am
content: Quote from: marshallh on January 02, 2015, 02:03:55 amIs that for the double sided adhesive tape as used on a lot of PC heatsink hardware?These heatsinks have no 'give' at all. Totally rigid - they feel like they are part of the PCB. Seems to be some kind of hard epoxy used to glue them on.