Echo and modem bit-rate problems
whitegreg56
Enthusiast - Level 2

So, I finally agreed to let Verizon put the boxes in my garage.  Ever since, my 56K dial-up modem has been connecting at 28,800 bps most of the time.  Only occasionally, will it connect at 52000 bps or 53296 bps.  Usually I have to dial-out a whole bunch of times to get a decent rate.  The Verizon tech said they don't deal with problems like this and said my house wiring was "moderately stressed".  So, I replaced the house wiring, myself.  The "loop" is only 100 feet long and I still have the problem.  I've noticed that when I place a phone call there is echoing on the line for a few seconds and then the echoing goes away.  I guess there is some processing going on.  When the modem is equalizing (at start-up) and this echoing is going on, I imagine that this is the reason for the low bit-rate.  Apparently, I don't have a "clear channel" for the modem to operate in.  Can anyone shed light on what to do about this problem?

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1 Solution
whitegreg56
Enthusiast - Level 2

Well, I've got a partial solution.  I did some web searches and found out that the Conexant chip set  my modem uses has a command that forces it to keep trying to connect between a set of bit rates.  In Windows Vista, click on Start, Control Panel, Phone & Modem Settings, Modems, Properties, Change Settings, Advanced.  Under "Extra Initialization Commands" I put in the string: AT+MS=V92,1,14400,33600,52000,56000.  The modem will keep trying to connect at a download bit-rate of 52000 to 56000 bits/second.  If it can't, it hangs up and redials.  So, I don't have to do it all, manually.

That said, I still believe the echoing is causing difficulty for the modem.  That is another project.

Back in the days of the Bell System, everything was specified in fine detail and pretty much guaranteed to work.  These days we have some really inexpensive telephone calls and next-to-nothing is guaranteed!

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Hubrisnxs
Legend

Hi there, 

So this started happening at or around the time the FiOS was installed?

is there anyway you can take your modem and connect it directly to the box and test?    How to Test Your FiOS Phone Line (ONT) | Phone ... - Verizon

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Hubrisnxs
Legend

In case there is something that you may not have thought of, I included this really solid FAQ.

I've only ever been able to get 48 max out of my 56 k modems.


Modems - Communications

A big collection of information about how to solve most of the common (and often highly irritating) problems with Modems and Data Communications. Included are discussions about dropped connections and what to do about them. This is the first place to look when you're having problems staying connected to HiWAAY.

Question: How do I make my 56K modem connect faster?

Answer:

Most people purchase a new 56K modem with the expectation that they probably won't get 56K speeds but that they will get significantly faster speeds than they did with their older 28.8K/33.6K (V.34) modem. Sometimes that does not happen; they find that their new connect speeds are the same or only slightly higher than with their old modem. There are several different causes for this behavior, sometimes you can do something about it and sometimes you can't.

Analog 56K modem technology requires that there be only a single digital to analog conversion in the telephone line. Thus, one cause is that simply the subscribers telephone line has two or more digital to analog conversions. This is usually caused by the fact that the telephone line is served by what is known as Subscriber Line Concentrator, often pronounced "slick". Telcos like Bell South use several different brands and models and have several different ways of connecting them into the telephone system. Not all SLiC's cause the behavior but some older models and some particular methods used by telco's introduce several digital to analog conversions into the subscribers local phone line, preventing connections faster than older V.34 modem speeds.

SLiC's are most often installed to serve pockets of high population density which are physicallydistant from the serving telco service center. Typically they are found in rural areas but sometimes serving large apartment complexes and in newly constructed housing subdivisions. They are very often used in areas with high concentrations of office buildings. Many phone lines in Alabama are served through a SLiC, although only a small percentage of those appear to introduce the speed limitation. If the phone line used with a new 56K modem is limited to older V.34 modem speeds by a SLiC, The telco must be contacted and convinced to alternately route the phone line directly to the central office or to upgrade the SLiC so that it does not introduce the limitation. There is no official mechanism for doing this, so calls to the telco order desk or repair center often result in frustration because the service representative does not understand the issue and has no policy/procedure to handle the request. Requests for repair of the line will usually be closed with a 'no problem found' status. Further, changes to remove the speed limitation are sometimes not technically possible or would be so prohibitively expensive that the telco can't afford to do them.

We have seen situations where a 56K modem that was connecting in the mid 40's suddenly stops and now only will connect at V.34 speeds. Many people don't realize that their telco is constantly rerouting phone lines. The most common situation is that an area suddenly starts growing, and the cable capacity for phone lines to serve the area is inadequate. Rather than pull more cable, usually the telco will install or expand a SLiC and move existing phone lines on the SLiC service, resulting in degraded connection quality.In this situation the subscriber can often complain to the telco and get moved back on to the directly connected copper cable.

There were two incompatible non-standard 56K modem protocols, one is termed K56flex and the other X2. Both have been superceded by a standard termed V.90 standard. It's not technically possible to offer a single dialup phone number which supports all three protocols. HiWAAY offers a V.90 preferred number in all cities which also supports the nonstandard K56flex protocol. In many cities we also offer a 'backup' number which supports V.90 and the nonstandard X2 protocol. When connecting to HiWAAY's preferred V.90/K56flex modems, the early proprietary X2 only modems are limited to speeds no greater than 33.6Kbps. In the same way, calling our backup V.90/X2 modems are limited to 33.6Kbps as well. This can be improved by upgrading the X2 modem to a new firmware version which supports the new 56K standard V.90 protocol, or perhaps changing to dialup an alternate number. However, we strongly recommend upgrading your modem to the V.90 standard.

Overwhelmingly, HiWAAY's subscribers report significant improvements in connect speeds upon their performing a firmware upgrade to their K56flex and X2 modems to the V.90 standard. We also observe the V.90 standard appears to overcome several types of line impairments in the callers local telephone loop. We suggest that any subscriber with a 56K modem using the non standard K56flex/X2 protocols, go ahead and perform the firmware upgrade to the V.90 standard. To our knowledge, free upgrades to the new 56K standard protocol are available from the vendors of all X2/K56flex only modems. Most 56K modems manufactured since about June 1998 also already support the V.90 protocol but you should check to be sure. Once upgraded to V.90, the original X2 or K56flex only modems connect well at full speed to HiWAAY.

HiWAAY maintains their modems at the most current release of 'non-beta test' firmware, and as long as the subscriber's modem contains a recent firmware version as well, the modem firmware is unlikely to introduce a limitation. However, the modem vendors are rapidly introducing new firmware versions and because of distribution delays, even a recently purchased 56K modem can have 'stale' firmware. Even when your modem already has support for the V.90 standard, we have seen firmware updates for modems cure a great many otherwise difficult to resolve problems. A visit to the modem vendor's tech support web site will usually reveal how to determine if more recent firmware is available and provide instructions for installing it in your modem. We recommend installing the most recent version of firmware for your modem which is NOT a 'beta-test' release.

Some 56K modems are connecting slower than expected because the line back to the telco Central Office is very long. Any thing over 18,000 cable feet will begin to degrade the quality of the signal. The longer the cable, the slower the speed. Sometimes requesting that the telco have your line be moved ON TO a SLiC can actually result in an improvement in your connect speed. The most modern SLiC's actually can improve the signal quality if the line from the SLiC back to the central office is "trunk side terminated".

Sometimes it is the way your call is routed by the telco to HiWAAY that can result in a slower connection. Often, a long distance call will route differently and even get addtional amplification by the phone company switch... which sometimes results in a faster connection. Try calling another HiWAAY location as a long distance call (for example if you are in Huntsville, try calling Florence), choose a HiWAAY access number that is served by an ISDN switch. If you get a better connect speed you may be able to complain to the telco about how your call is being routed or the quality of the equipment it is being routed through.

If the subscriber modem is getting low to mid 30's connect speeds, for example 32000 or 34000, or is very erratic in the connect speed, then the problem may be an impairment in the subscriber's telephone line which can be repaired. There are a number of different problems, such as ground loop, bridge taps and other wiring faults which can limit the speed of 56K modems to the low 30's. Most often these problems are found in the subscribers premise wiring in their house or in the drop from the curb to the house than in the outside telco wiring. In HiWAAY's experience, by far the most common reason for modem connectivity problems such as slow connect speeds, poor performance and frequent disconnects is a problem with the telco wiring in the caller's house or curb drop! Getting it repaired often requires a methodical approach to finding and correcting the problem and great patience in dealing with the phone company.

A related local loop issue is that we have observed most V.90 modems are VERY sensitive to your house telephone wiring and the way the modem is actually connected to house telephone jack. We find that connecting several devices in a 'daisy chain' (wall jack to answering machine to modem to fax machine for example) will slow connections or make them unreliable. Various types of 'surge protectors' made for phone lines also will slow your connection. Having a lot of phones and related devices (like caller id boxes) on other extensions will also almost certainly slow down your connection speed and even cause disconnects.

Finally, it's possible you may actually be getting a good 56K connect but your modem is not reporting the true connect speed or your software may be reporting it incorrectly. This is very common where 'generic' modem drivers are used with MS Windows, and seems to have become more noticeable a problem with V.90 compatible modems. Make sure you have your serial port speed on your COM port set to at least a speed of 115.2K... many modems will not report a connect speed any faster than the speed of the serial port speed. If that's not the problem, visit the vendor support web site for your modem. Then download and install an appropriate Windows .inf configuration file for your particular make and model.

Our recommended approach to trying to remove a limitation on 56K modems is a follows:

1Double check your software configuration settings to be sure appropriate make and model have been selected and that the COM port speed setting is at least 115.2K or greater. If your modem vendor offers an updated Windows .inf configuration file for your make and model, we suggest installing it.
2Contact the tech support of the vendor for the modem and make sure the modem is at current firmware revision level or that their support department is not aware of any particular issues associated with your modem. Make CERTAIN your modem supports either the V.90 or K56flex protocol standard. If your modem vendor offers a non-beta fully supported V.90 firmware upgrade, we suggest performing the upgrade.
3Try making a long distance call to another remote HiWAAY access number. If this results in a significantly improved connection speed you can skip to step 6, because you have learned that the impairment is in your call routing not in your line.
4Unplug EVERYTHING from the all phone jacks in your house, try connecting with just a single cable from your wall jack to the modem with no other phones or devices connected to the phone system anywhere else in the house. If you have more than one telephone line in the same house, try them all. If possible try another phone line at another location. If any of this results in a significantly improved connection speed, then you can rule out a modem or computer configuration problem.
5Isolate the phone line from house wiring by disconnecting the house wiring from the telco network demarcation block and connecting the modem directly to the network demarcation block. If this works, there is almost certainly a premise wiring fault of some kind and you will have to use trial and error to find the fault.
6Try another brand and model modem. If this results in a substantially improved connect speed, then the limitation may be modem firmware compatibility or just plain modem quality. Some modems handle some types of line impairments much better than others.
7Call the phone company and request a repair on the line, insist on actually meeting the repair person at your house and ask him to tell you how the line is "provisioned". (How far is it from the CO? Is served by a SLiC?) When talking to the phone repair person, if you feel they are not sympathetic to the issue then ask for their supervisors name and phone number, call and request another repair person.
8If all these steps do not result in finding a cause which can be corrected, we suggest considering ISDN which WILL provide vastly superior performance and reliability over any analog modem.

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whitegreg56
Enthusiast - Level 2

Thanks for that info.  I know that the (electrical) echo is due to a mismatch

at both ends of the line.  I'm still wondering why the echo goes

away after a while.  Maybe a Verizon engineer can explain what

is going on.....apparently it's not just a "clear channel".

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whitegreg56
Enthusiast - Level 2

I noticed something else.........I opened the customer access panel on the box in the garage.

There is an LED that says "DATA" next to it.  That LED is blinking on and off.  It stays "on" for

5 seconds and "off" for 30 seconds.  I'm wondering if that is indicating some problem.

The other LEDs do not blink.

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whitegreg56
Enthusiast - Level 2

Well, I've got a partial solution.  I did some web searches and found out that the Conexant chip set  my modem uses has a command that forces it to keep trying to connect between a set of bit rates.  In Windows Vista, click on Start, Control Panel, Phone & Modem Settings, Modems, Properties, Change Settings, Advanced.  Under "Extra Initialization Commands" I put in the string: AT+MS=V92,1,14400,33600,52000,56000.  The modem will keep trying to connect at a download bit-rate of 52000 to 56000 bits/second.  If it can't, it hangs up and redials.  So, I don't have to do it all, manually.

That said, I still believe the echoing is causing difficulty for the modem.  That is another project.

Back in the days of the Bell System, everything was specified in fine detail and pretty much guaranteed to work.  These days we have some really inexpensive telephone calls and next-to-nothing is guaranteed!

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