Hello everyone, I've played SR for years but have only recently started playing as our groups hacker, so I'm trying to understand how things work.

How am I to determine the location of a device (commlink, drone etc.) once I have picked up it's signal?

Example: We are meeting the Johnson at a restaurant. While sitting at the table I decide to hack the Johnson (whether this is a good idea or not doesn't matter), so I begin running a scan and pickup various wireless signals. This is a crowded restaurant so not only do I detect the Johnson's commlink but also his goons along with all my runner partners not to mention everyone else in the place. Without the SIN or commcode ID# how am I to determine which signal belongs to the Johnson?

That's an interesting question. I don't personally know the direct answer.

Honestly, it's simpler to go from location to signal than the other way around. You point at the Mr. Johnson and say, 'I Detect Hidden Node for the commlink he must be carrying'; you roll a Electronic Warfare + Scan (4) Test.

Remember that, "You automatically find all of the nodes within Signal range that are in Active or Passive mode." So Hidden Mode is the only thing you'd worry about. You'd be able to 'glance' at all the others and see their Facespace profiles, complete with photos; you could possibly also access their geo-location data (with or without hacking). An Agent or two can make this sort of low-level awareness easier.

Another option is to Capture Wireless Signal and see if there's anything recognizable in there. Encrypted signals could be a tip-off, as well.

In terms of baldly going from 'I know there's a Signal here, where's the node located?', I don't think you can get closer than 50m (as stipulated by Trace User); after all, after you've traced them to their 'home' node, that's as far as possible. With reflections and noise and things, it seems fair, even compared to triangulating 'by hand' with a team.

1) Find out how many are encrypted, rule out any that aren't
2) I would have you do a EW+Analyze to determine the signal strength of the various nodes.
3) ew+decrypt to unencrypt the signal
4) ew+sniffer to grab the traffic
5) computer+analyze to get the commcode
6) Voila

That's actually more than the book really requires; Detect Hidden Node lets you say 'find *his* commlink', and then it's simple hacking to get the Access ID, last commcodes used, etc.

sabs, I'll run that past my GM. But there has to be an easier way to determine the signal location. The fluff in the main book would seem to indicate that, on page 206 it describes being able to notice people in the immediate vicinity "whether you want to read that hot elf's profile". You would have to be able to tell the difference between the hot elf's signal from the butt ugly troll.

I'd looking into telematics Infrastructure software (unwired p.62)

"Telematics Infrastructure
Telematics Infrastructure (TI, pronounced “tie”) is a tracking system for vehicles, drones, and personnel. It works via a network of TI programs running on individual commlinks, devices, and
even RFID tags. It combines sensor data, GPS information, and wireless scanning to detect and track all individuals within its boundaries and report anomalies.

TI will automatically detect and report any wireless device in Active or Passive mode that enters its coverage area. Various parts of the network also scan for Hidden nodes; use the rules for Detecting Wireless Nodes as an Extended Test (p. 225, SR4) except that the TI system makes only (Rating) rolls per minute and scans its entire coverage area.

The information generated by the TI network can be fed to a TacNet (p. 125) or any other user or device that is “TI’d into the system.” This information includes the position, direction, and speed of any wireless device within the coverage area, along with its access ID and any public data offered by the device."

Yerameyahu touched on this, but this is a key point. There are not 50 "signals" in your search results. There are 50 -meaningful results- in your search, and those results all have data about who they are. 47 of them have profiles which pop up in your AR by their sources. Each of them has enough identifying information gathered from your search to tell whose they are. The other 3 aren't going to be utterly blank, data-less "signals" either even though they're in hidden mode. You could probably glean what their OS is and narrow down what model they have as well as get a good idea of where they are in relation to you if they're that close. As a GM I've run into the very same question in a recent game with a new player running a hacker, and I found it best not to overcomplicate it. If you can detect the hidden node, in most cases you should let them find the one they're looking for and let them go from there. It doesn't pay to make things unnecessarily complex in an already complex game.

Mesh

I know about the TI system, but I figured it required a lot of hardware to make it work.
I was hoping for a simple solution like the AR overlay indicated where the signal originated from if you happen to be within sight of the device.

Most Commlinks and devices in public mode will simply tell you where they are. Do a Matrix Perception test if you need a die roll for it.

How you explain it in fluff is up to you.

A simple explanation is that if there are fifty devices and forty nine quite happily tell you where they are, the 50th is the one left over.

I figured it had to be as simple as that, how else would Lonestar know who was walking down the street that was not broadcasting in active or passive mode. Now I just need to convince my GM, I wish the rules would directly state it.

You can run Analyze on a Node to gain information about it. Once you have a list, narrow it down with some common sense, logical eliminations, etc. Then Analyze the few that remain to get some info, such as OS, a Node description/type, if it's encrypted, if it has a databomb, etc.

So it is possible to run an Analyze on a node that you do not have access to, not to put you on the spot but is that clearly stated in the rules? I'll need to read through it more carefully.

Yes, but depending on it's security settings you may not be able to get as much info. The basic list on SR4A p228 should mostly be accessible info but some may be privileged and not all apply to nodes, and not all apply to Matrix Perception from OUTSIDE (IE: not hacked into yet) the node.

The node's rating of an attributes, function (example: "Commlink", "Hermes Ikon", "Coffee Machine", "Bunn CBS 5000", "Automobile", "Security Camera 01023-95", etc; though a hacker could edit this), presence of a data bomb, that the node is encrypted, and the node's Access ID should all be fairly universally available though through a Matrix Perception test even if conducted from outside the node.

Just my thoughts.

Though for the LS example, its more a 'they detect you're not broadcasting' as opposed to 'they detect you're running a hidden mode link'. The difference also being that you might also have 3 hidden mode commlinks on you at the same time, they're not detecting your nodes, they're detecting the fact that when you walk by you dont have a HI LOOKIT ME I"M LEGAL broadcast going. In the SR fluff example, its compounded by the fact that the runner in question is solo. Might be easier to pull off in a crowd, but walking by yourself is akin to no cover.

Which is also why you should be running a decoy commlink in 'public' sectors, to at least pretend you're on the up and up.

What you could do is get an electroreceptor symbiont. I couldn't think of a way to find the node's location via software save hacking the node and hoping it's linked to GPS, or getting some custom software to triangulate it's position based on signal strength in relation to two other nodes.

You scan, you find 50 nodes. You then ask the 49 nodes who will quite happily tell you who they belong to and where they are if any of them can also tell where that extra 50th node is with your Matrix perception test. The rest of the Matrix, who don't belong to hardened criminals is designed to make it easy to know where things are, and to know where each other is. If you've scanned out the odd one, it seems reasonable to take advantage of the straightforward standard routine that every other commlink has to find out where other commlinks are.

Note that finds you the node's relative physical location. If you want to access the Johnson's node, you still need to logon to it and then perform the usual hacking + exploit to gain access, and then a Matrix Perception test to discover what's in it, and then a data browse to look for specific items. To access the node this way, you don't need to know it's physical location.

I leave the details abstract and just get along with the game. If the Johnson was in Active or Passive Node, I just have the hacker make a Matrix Perception test and I set the threshold to how hard I think it will be. Success means he found it. If the Johnson is in Hidden mode, then the rolls the hidden node scan test. Success means he found it.

On the other hand, there's no reason that an experienced Mr J wouldn't be able to run the same type of tricks as runners. A fake decoy 'public' commlink. A fake decoy hidden commlink. And a sorta-real commlink turned off during a meeting.

As a Mr J, I would not actually carry my real commlink on me, when meeting a runner team. It would be safely tucked away in my office.

I have my fake commlink which I carry on me.
I have a fake commlink in my vehicle that I can use to get back to my office, but isn't actually me.

If I get nabbed, well my corporation will probably disavow me.
If they don't, I can use my dna and a retinal scan to prove my identity.

You don't even have to have a 'real' commlink, which I assume means 'your computer with everything on it'. Given that everything is wireless and storage is unlimited (and so is bandwidth, more or less), you just need terminals.

well in real life (yeah I know this is a game but whatever) you would be able to generally know what circuit/connection by knowing the physical location. You would then have to get them to do something specific then (google seach, jump onto msn messager, whatever) and keep doing that till you narrowed the list to 1.

bah, hit enter to early. One moment, fixing.

The Browse program.

You do an extended find Nodes test, which gives you a list of every device within mutual signal range.
Then you browse through, using the Browse program's innate functionality to sort through data and find the relevant information.

As to seeing nodes, I imagine that they operate in the same manner as AROs for any active node. Passive and hidden nodes should still be a simple matter to triangulate in a regular wifi-saturated environment.

Yes; you can triangulate them down to 50m. A house rule might be in order.

The thing about signal is that it's not directional, it's a radial signal which "pings" commlinks for information. A commlink on hidden wouldn't be broadcasting any AR constructs, and the radial ping wouldn't be able to pick up where it is. You'd have to triangulate. Alternatively, you could have a custom virus that makes it broadcast an AR construct on a non-standard frequency.