Sorry, should have hit preview, part of my replay got cut (Must remember don't use angle brackets). It should look like this: The problem is DOCSIS won't be only using frequencies below 55 MHz. The upstream frequency will, but the downstream frequency will be above that. That is the one that will need a custom made window filter to isolate that 1 channel. Some Band pass filters are cheap, but for something like this you would need a filter with a very sharp frequency cutoff in order to isolate a single channel without allowing any bleeding of adjacent channels. That type of tolerance will not be found in a simple $5 part. Why won't the cable company do that? That would be alot of work for a small number of customers. For the prices most cable companies charge for cable modem service, would the extra support needed for this 'non-standard' setup be worth the returns? I would think that most cable companies wouldn't even consider it
The problem is the DOCSIS won't be only 55MHz. That is the one that will need a custom made window filter to isolate that 1 channel. Some Band pass filters are cheap, but for something like this you would need a filter with a very sharp frequency cutoff in order to isolate a single channel without allowing any bleeding of adjacent channels. That type of tolerance will not be found in a simple $5 part. Why won't the cable company do that? That would be alot of work for a small number of customers. For the prices most cable companies charge for cable modem service, would the extra support needed for this 'non-standard' setup be worth the returns? I would think that most cable companies wouldn't even consider it
Actually, the Cisco uBR 7111 is only around $8k. As for getting service from a cable company, and combining the cable modem signal onto the internal cable, would any cable provider do it? Since the cable company would only be allowed to insert the docsis signals, they would you need to use some kind of windowed filter set for the specific frequencies they use. That would have to be custom made. And when (not if) the docsis carrier is moved to another frequency, or another frequency is added, a new custom windowed filter would have to be made. Depending on the cable company, they may be willing to install a small CMTS at the apartment complex and insert directly into the aparmtment complex, but at that point you'd probably be looking at a cost around the same as getting a small cmts yourself.
Since the management company essentially has there own cable plant, they can add anything they want to it. In order to have cable modem service, they will need to install some kind of CMTS (Cable Modem Termination System) and use that. CMTS are basically routers with RF catv ports on them. The CMTS will have at least 2 RF ports, one for upstream and one for downstream. Both of the ports will need seperate RF channels, although the upstream channel does not need to be on a channel used by normal tv signals. Most CMTS systems will provide the downstream signal on an intermidate frequency and need a seperate upconverter to translate the signal to a frequency that can be combined with the standard tv signal. For a single apartment complex, try looking at a Cisco 7111 uBR(IIRC the 7111 is one of the few Cisco CMTSs that have a built in upconverter).
This isn't quite true. CMTS's can be configured to bring up modems so that the pass all traffic through with no filtering. We use standard CMTS's and CM's to provide service to hotel customers and one of the management systems we evaluated needed to have all CPE devices on a flat network. Every CMTS we've looked at so far has had that ability.
While I can't speak for others, this is what worked for me. I started with messing around in college where I was supposedly working on a CS degree and instead was spending time playing games all day and eventually getting kicked out. With this kind of start I must have done something right later. One of the guys that I spent my college years playing MUDs with eventually got a job at the school and set up a UNIX box to host his own MUD. He invited me to help maintain the mud and gave me root access. This was my first experience as an 'administrator' and I did nothing. I just watched what he did when something had to be fixed. Eventually he dragged me to a Linux user group meeting and after the meeting (where I didn't say anything, just sat there and nodded my head every so often) I had a long list of things I didn't understand. I spent the next month looking up what they were talking about on the Internet. For each monthly meeting I did the same until I got to the point where I could actually join the conversation. That took about a year, it probably would take less if I had asked one of them for help, but in those days that LUG wasn't newbie friendly. During that year I had also taken one of the linux cd's that were being passed around (Caldera 1.1 IIRC) and installed it on a computer at home (A 386 that a friend was planning to throw away) and started playing with it. By this time the LUG I was in had a change of administration, the guy in charge of the LUG moved to another state. The new LUG was re-inventing itself as a group accessible to newbies. Since I was already comfortable with Linux systems I starting helping all the new members whenever I could and pretty soon my name kept appearing on the groups mailing list with answers and little shell scripts. A year later I went back to school, this time a community college and started working on an AS in CS (which at the 2 year level is a joke) and this time actually tried to learn. After 2 years of unemployed loafing around, I knew I had to turn my life around. I managed to get a job at the community collge as a student assistant in the computer center and spent 3 semseters there mostly fixing broken computers (replacing parts usually). During my 3rd semster I took a class on computer repairs, and thanks to my (at that point) 1 year of doing just about nothing but repairs, I aced that class. The teacher was impressed and asked if I would like to do an intership with his company (He was teaching as a side job). I said yes, and when my application was being processed, I found out that the senior adminstrator was subscribed to the LUG's mailing list and recognized my name from it. He forced my name through the HR dept. and I when I went to the interview for the internship posistion, the HR person said the interview was just a formality since the senior admin would only take me from all the applicants. I then spent about a year and a half as a part time intern (yes I took almost 3 years to finish a 2 year program. At this time was trying to juggle 2 part time jobs, school, a 'non paid admin' on a MUD server, learn as much as I could about being a system admin, and have a social life). When I finally had graduated with honors (Amazing what you can do when your determined) and got promoted to a full time administrator for about 2 dozen UNIX boxen.
To sum everything up, the most important thing I did was join a local technical group and become a visible, active member. In addition to my current job, my LUG membership has gotten me a few other good offers including an out of state deal that I would have jumped at if the timing was better (offered to pay my way through a full 4 year degree and give my paychecks as a part time intern untill I made the degree requirements for the actual position). If you don't have any 'real' job experience, alot of visiblity in the technical fields can work just as well. If I can do it then just about anyone can, you just have to be willing to work harder for it.
Unfortunately, you can't just hook up 2 cablemodems together and expect them to talk. You also need to get a broadband router with a cable module, and they're not exactly cheap. Basically, when a cable modem comes on line it needs to search for a forward and return carrier, then download its configuration settings through the cable connection.
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Sorry, should have hit preview, part of my replay got cut (Must remember don't use angle brackets). It should look like this:
The problem is DOCSIS won't be only using frequencies below 55 MHz. The upstream frequency will, but the downstream frequency will be above that. That is the one that will need a custom made window filter to isolate that 1 channel. Some Band pass filters are cheap, but for something like this you would need a filter with a very sharp frequency cutoff in order to isolate a single channel without allowing any bleeding of adjacent channels. That type of tolerance will not be found in a simple $5 part. Why won't the cable company do that? That would be alot of work for a small number of customers. For the prices most cable companies charge for cable modem service, would the extra support needed for this 'non-standard' setup be worth the returns? I would think that most cable companies wouldn't even consider it
The problem is the DOCSIS won't be only 55MHz. That is the one that will need a custom made window filter to isolate that 1 channel. Some Band pass filters are cheap, but for something like this you would need a filter with a very sharp frequency cutoff in order to isolate a single channel without allowing any bleeding of adjacent channels. That type of tolerance will not be found in a simple $5 part. Why won't the cable company do that? That would be alot of work for a small number of customers. For the prices most cable companies charge for cable modem service, would the extra support needed for this 'non-standard' setup be worth the returns? I would think that most cable companies wouldn't even consider it
Actually, the Cisco uBR 7111 is only around $8k. As for getting service from a cable company, and combining the cable modem signal onto the internal cable, would any cable provider do it? Since the cable company would only be allowed to insert the docsis signals, they would you need to use some kind of windowed filter set for the specific frequencies they use. That would have to be custom made. And when (not if) the docsis carrier is moved to another frequency, or another frequency is added, a new custom windowed filter would have to be made. Depending on the cable company, they may be willing to install a small CMTS at the apartment complex and insert directly into the aparmtment complex, but at that point you'd probably be looking at a cost around the same as getting a small cmts yourself.
Since the management company essentially has there own cable plant, they can add anything they want to it. In order to have cable modem service, they will need to install some kind of CMTS (Cable Modem Termination System) and use that. CMTS are basically routers with RF catv ports on them. The CMTS will have at least 2 RF ports, one for upstream and one for downstream. Both of the ports will need seperate RF channels, although the upstream channel does not need to be on a channel used by normal tv signals. Most CMTS systems will provide the downstream signal on an intermidate frequency and need a seperate upconverter to translate the signal to a frequency that can be combined with the standard tv signal. For a single apartment complex, try looking at a Cisco 7111 uBR(IIRC the 7111 is one of the few Cisco CMTSs that have a built in upconverter).
This isn't quite true. CMTS's can be configured to bring up modems so that the pass all traffic through with no filtering. We use standard CMTS's and CM's to provide service to hotel customers and one of the management systems we evaluated needed to have all CPE devices on a flat network. Every CMTS we've looked at so far has had that ability.
While I can't speak for others, this is what worked for me. I started with messing around in college where I was supposedly working on a CS degree and instead was spending time playing games all day and eventually getting kicked out. With this kind of start I must have done something right later. One of the guys that I spent my college years playing MUDs with eventually got a job at the school and set up a UNIX box to host his own MUD. He invited me to help maintain the mud and gave me root access. This was my first experience as an 'administrator' and I did nothing. I just watched what he did when something had to be fixed. Eventually he dragged me to a Linux user group meeting and after the meeting (where I didn't say anything, just sat there and nodded my head every so often) I had a long list of things I didn't understand. I spent the next month looking up what they were talking about on the Internet. For each monthly meeting I did the same until I got to the point where I could actually join the conversation. That took about a year, it probably would take less if I had asked one of them for help, but in those days that LUG wasn't newbie friendly. During that year I had also taken one of the linux cd's that were being passed around (Caldera 1.1 IIRC) and installed it on a computer at home (A 386 that a friend was planning to throw away) and started playing with it. By this time the LUG I was in had a change of administration, the guy in charge of the LUG moved to another state. The new LUG was re-inventing itself as a group accessible to newbies. Since I was already comfortable with Linux systems I starting helping all the new members whenever I could and pretty soon my name kept appearing on the groups mailing list with answers and little shell scripts. A year later I went back to school, this time a community college and started working on an AS in CS (which at the 2 year level is a joke) and this time actually tried to learn. After 2 years of unemployed loafing around, I knew I had to turn my life around. I managed to get a job at the community collge as a student assistant in the computer center and spent 3 semseters there mostly fixing broken computers (replacing parts usually). During my 3rd semster I took a class on computer repairs, and thanks to my (at that point) 1 year of doing just about nothing but repairs, I aced that class. The teacher was impressed and asked if I would like to do an intership with his company (He was teaching as a side job). I said yes, and when my application was being processed, I found out that the senior adminstrator was subscribed to the LUG's mailing list and recognized my name from it. He forced my name through the HR dept. and I when I went to the interview for the internship posistion, the HR person said the interview was just a formality since the senior admin would only take me from all the applicants. I then spent about a year and a half as a part time intern (yes I took almost 3 years to finish a 2 year program. At this time was trying to juggle 2 part time jobs, school, a 'non paid admin' on a MUD server, learn as much as I could about being a system admin, and have a social life). When I finally had graduated with honors (Amazing what you can do when your determined) and got promoted to a full time administrator for about 2 dozen UNIX boxen.
To sum everything up, the most important thing I did was join a local technical group and become a visible, active member. In addition to my current job, my LUG membership has gotten me a few other good offers including an out of state deal that I would have jumped at if the timing was better (offered to pay my way through a full 4 year degree and give my paychecks as a part time intern untill I made the degree requirements for the actual position). If you don't have any 'real' job experience, alot of visiblity in the technical fields can work just as well. If I can do it then just about anyone can, you just have to be willing to work harder for it.
Unfortunately, you can't just hook up 2 cablemodems together and expect them to talk. You also need to get a broadband router with a cable module, and they're not exactly cheap. Basically, when a cable modem comes on line it needs to search for a forward and return carrier, then download its configuration settings through the cable connection.