I have one round wire (probably coax, although it has no specification info marked along it, the way the cable for the satellite did). It goes to the box shown in the picture below which seems to only be for cable, not DSL, based on the phone box pictures I saw online. Is this correct?

Yes, that is coaxial cable. Used for television, Internet service, and sometimes digital telephone.

It's hard to describe this wire; part is round, and then there's a small round, detachable part which they used to wrap the loop they created where they attached it to the house.

This second portion is called messenger wire. It's a steel cable which is either part of the coaxial cable or run above it to bear the weight of the coax. On long runs the messenger wire is needed to avoid over straining the coax cable itself.

Up in the attic, there is a black, flat cable that comes in (see picture below which shows it on the outside), about 1/8" thick, 1/4 inch wide. I think that's probably commercial HDMI cable - it looks like that from online pictures - but could this be DSL?

It's POTS (Plain Ol' Telephone Service) cable which can be used for telephone and/or DSL.

 

... This second portion is called messenger wire. It's a steel cable which is either part of the coaxial cable or run above it to bear the weight of the coax. On long runs the messenger wire is needed to avoid over straining the coax cable itself.....

It's POTS (Plain Ol' Telephone Service) cable which can be used for telephone and/or DSL.

One clarification: your picture shows the coaxial cable with the messenger wire, correct?

I wanted to clarify since the picture followed what you said about POTS (but that's probably because pictures seem to only get attached to the end of posts) The flat black cable (the one you said is POTS) is truly flat on the outside - no indentation at all.

 

The cable that the phone company uses from the phone box on the outside wall to the main phone jack inside the house will sometimes be a somewhat black or beige flat two-pair cable, not to be confused with HDMI cable or RJ45 wire. Look very closely at it and you might see some printing or some molded-in writing on it. It's also less flexible than data cables since it's solid copper.

 

Picture #1, the large wires (one with white tape) going into your weatherhead are your line voltage (120 v each),so stay away from them !!

Picture #3 show cable (TV) only.

DSL comes in over your phone line and is filtered with internal filters on each point of access, or in the NID. It uses a different frequency than voice, so they can use the same lines.

The middle picture is an HDMI cable. It will only be used between your DSL modem, VCR, Satellite box, etc. and your TV.

 

Picture #1, the large wires (one with white tape) going into your weatherhead are your line voltage (120 v each),so stay away from them !!
Yes, that wire is why I haven't messed with the others; thanks for the warning though

The middle picture is an HDMI cable. It will only be used between your DSL modem, VCR, Satellite box, etc. and your TV.

I have a cable that looks like that coming in to my attic through the house wall right behind the mess of wires in the picture. It must be coming off that mess of wires. Is is possible that they ran the HDMI-like cable off of the outside wires?

 

Here's a closeup of that bundle of wires - you can see that the wire that is in a circular bunch is the flat, black, 1/4 inch wide cable that looks like commercial HDMI.

Edited: added second pic with mystery cables labeled.
The flat black wire is the one on the left that goes into the house, but it also continues on to the neighbors houses. The cable on the right going into the house is just a round one (like coax) - yet another mystery cable.

The label nearer the bottom just says "round cable (like coax)" - you can read that if you click on the pic to zoom it.

 

Thanks for all the replies. Fewer mysteries now.

 

If you have phone service, you have DSL. It is run on the same cable. See post 2. HDMI is only used between inside apparatuses. The reason the cable in the attic has no messenger wire is because the support provided by it is not needed

 

Update: last summer, new people moved into the house next door to me on north side (pole is in yard of house next door to me on south side) and needed new telephone cables. Telephone guy talked to me because he needed to access the telephone wire to that house which were attached to a hook on my house. He said the neighbor's wires never should have been hooked up to my house. There were also some other problems with the telephone wires between the pole and my house. He also said the cable to my house was old enough that if anyone got a landline or wanted DSL through Century Link, it would need to be replaced (I haven't had a landline in the 11 years I've lived here; also can't stand Century Link). He recommended just removing the wire to my house as well. I was concerned that would have a negative effect on me if I sold, but he said it wouldn't since cable is so old. I finally just agreed & he clipped it at outside of house & caulked the hole.

Had also been trying to get the cable company to remove another old cable which ran between the neighbor's house (on north) and pole. Unsurprisingly, they were completely unhelpful. But luckily, in a wind & ice storm, it fell down. The previous neighbors said they had never used that cable and they'd been there 20 years. If there hadn't been the storm, I don't think the cable company would have ever resolved this problem.

 

Technology has changed the way we wire things for sure. I never thought I would have full internet service telephone, and TV reception all wirelessly on my 1 cell phone. Thank of all the money spent wiring the towns for the upcoming technology in the 70's to be mostly unused now.