modem speed

[jnas]

I have a 56k Fax/Data/Voice modem and from day one all I've been able to run is 26400 on my internet connection. I replaced the phone wire all the way from the telephone companys box to the computer with cat5 wire
somebody please help.

[Ekim]

Hi,

Does your ISP support speeds higher than what you are getting? I have a friend who had a 56k modem too, and he only got speeds of 1900 because his ISP was SH*T http://www.sysopt.com/forum/smile.gif

Mike

[jnas]

My ISP supports 56k and is everyones internet. which is big here. But how do I check to make sure that they are not the problem.

[Red Rage]

Theory is...

If there is more than one analog to digital conversion in the route to your ISP then you cannot get 56k speeds. Even 33.6 may not be available.

Thats what they say but heres what I find.

Certian modems handle multiple conversions better, The USR/3com Courier is one of them. Most Soft/WinModems handle them very poorly.

Things to try to test this, Try taking your computer to a friends house that you know connects faster and see what yours does. If it does the same thing its either your modem or a setting somewhere (prolly the modem), if it connects fast then you know its either your line or the way your call gets routed through the phone system.

Some things you can do if its the phone system.

If it is the phone system you can ask your ISP if the have another number local to you, your call may get routed differently.

See if caller ID is available to you. if it is order it for one month. If your switch at the Main office is older it will force them to replace it. (make sure to cancel after the 1st month if you don't want it)

call and complain about intermitent static on your line mainly when it's wet outside. then ask them to rewire from the pole to the box.

the last resort, get a 56k USR external from Staples, throw it on and see how it does... if it doesn't work well you can always return it, if i remember right, they're good about returns.

Hope this helps,
~Red

[Red Rage]

Hey Banti,

I think my brain just died... Had to read that about 8 times to follow it..

I don't suppose you can Post or give a link so that I can get more info on robbed bit signalling could you?

Thanks in advance

~Red

[Banti]

Actually the A/D conversion is not the problem. Some telco trunks use a communication scheme called robbed bit signalling. This siganalling is the communication channel from trunk to trunk. With speech you cannot tell, but computers trying to reach high speeds (w/modem) on the telephone line will faulter at high speeds. This will cause 28.8 to be the max speed.

(completely different topic) 56k is a simple trick (not compression or A/D related), use both coppers two talk or listen. If the computer listens with both it will recieve at 56k, if it talks with both it will send at 56k.

Red Rage's suggestions might work for you, but chances are that your trunks is the area are not that old. The tech used to connect you to your ISP is from the mid-80's The ss7 signals for caller Id have been around since ISDN... actually they make ISDN possible. SS7 signalling is what makes caller ID, call forwarding and a slew of new services possible. SS7 replaces robbed bit signalling.


(These are simply tests I thought might work)
One other alterative... if they offer ASDL in your area... have them run a line check.... if it passes and the noise level is low.. try a friends modem, also try a BBS that runs at 56k or try to connect to another 56k modem.

Best of Luck,
Banti

[This message has been edited by Banti (edited 01-11-2000).]

[Banti]

Sorry, I will edit the post... I was tired and high on coffee.

About the robbed bit, I will try. Bell Labs made it a communication standard, but I do not know if the public gets to see it.

Will post back with link, if legal.

Banti

[Banti]

Here is the skinny on bit-robbing.

Voice is digitized into bytes (8bits) this happens 8,000 times a second. Multipling these numbers gives us the 64kbps limit (analog) on DS0 lines (the kind running to our houses). Back when the big wigs made all of the important decisions, they had two options for siganlling between digital trunks, in-band (bit robbing) and out-of-band (ss7). I guess in-band is cheaper so alot of people choose this. Every sixth frame, the least significant bit is rewritten with data from the trunks. So every six frames, there is one bit of voice data missing. These bits add up over time, and the are on both the sending and recieving of data from the modem. This loss of resolution causes modems to handshake at a lower baud rate.

Here is link, it is the best I could find. Hopefully, this will prove to you that I am not blowing smoke up your *** http://www.sysopt.com/forum/smile.gif.

http://www.its.bldrdoc.gov/fs-1037/dir-005/_0636.htm

Books that are handy
Newton's Telecom Dictionary (Like $30US at Barnes and Noble)
The Telecom Encyclopedia (Have heard it is at B&N, but haven't found it yet)

Banti


[This message has been edited by Banti (edited 01-11-2000).]

[Red Rage]

Its not that i think your making it up, its just I would like to know more :-)

I did some searching my self and found some stuff form Cisco and dialogic. Really intresting. Bell Labs has nothing there :-(

But from what I'm understanding from your posts. (In General) If you can't get caller id in your area, then chances are you can't get ISDN. Would that be correct?

Now lets try this, The Phone Co. just started offering Caller ID in your area. If you where to get it that would switch you over to SS7 instead and eliminate Robbed Bit on your end. Would that be correct?

Then you would just have to worry about the ISP's Trunks. But If the ISP Can support ISDN on their Equipment and Lines would that also mean that they would be using the SS7? Thus Rulling out Robbed Bit all togeather?

Or am i just talk'n out my ****? :-)

Thanks,
~Red

[Red Rage]

I'm in Western PA almost exactly in between Erie and Pittsburgh.

A/D conversions may not be needed but the alot of the system here is 20-30 yrs old. GTE is starting to update, Bell has been updating for some time and they say ADSL will be available a few months ago, Sprint (formally Altel) is soooo far behind i don't think they'll ever catch up, and Venus well they got like 6 human and 50 deer as customers so I don't think their worried to much.

Most people in this area seem to connect at 28.8 or lower but people in the updated areas do connect at 56k speeds (if they got a 56k)

~Red

[jnas]

sorry i been away for a while thanks for all the information but so far all ive figured out is that i need to try a different area and a different modem. is there anything i can do here to test it or speed it up. i do have caller id but i am in a rural area.
its amazing but tonight im running at 28.8


[This message has been edited by jnas (edited 01-11-2000).]

[Banti]

Bell Labs would not place there docs in the open.

The problem with trunks is that it only takes one to enable the robbed bit problem.

I connect to your modem.
Trunk 1 has ss7 and no robbed bit
Trunk 2 has ss7 and no robbed bit
Trunk 3 may have ss7 but does have robbed but

Me--T1--T3--T2--You

We both suffer from this. If I remember correctly, the predecessor(sp?) of ss7 allowed ISDN to work. So ss7 should ensure ISDN, but not the other way around.

If you have caller id in your area, yes your trunk should not use robbed bit signalling, but that does not ensure other trunks that it needs to connect to do not (as per the diagram above).

BTW you do not have to buy caller id to have ss7 enabled. It is an upgrade that the telco has already performed(that is if they offer the service to you)

Hope this helps,
Banti

[Red Rage]

Geez Do you live here? :-)

Well The phone companies in the this area.. well.. are a pain to say it mildly and to make matters worse there a quite a few of them. And they all like to do things backwards.

Any way, I just found out that it is possable to setup ISDN on Robbed Bit as far as equipment goes.

I got the basics ( i think), If any of the trunks have Bit Robbing on then, you MAY get stuck at 28.8 speeds.

But if Bit Robbing is Disabled on the route then you "should" get 56k speeds, depending on line noise.

Ok soooo... if they users trunk is set at the switch to use Bit Robbing, Getting Caller ID would disable it, removing it from his/her end. And IF ( notice thats a big one ) All the other Trucks are disabled it would correct the Bit Robbing problem.

But then again if you can configure ISDN to work with Bitrobbing then one could assume that CallerID could be too.

Argh I think i'm going to have to buy a book.

Now, Certian modems do handle bit robbing better? I assume its a yes because when one always gets 26.4 on say an Acer56 and they put in a USR 56k they usually get better speeds.

Thanks!
~Red

[Red Rage]

Oh a note about A/D conversions I just found this as well. Not much info but it does confirm what I orginally said is possable :-)

http://aos.ascend.com/aos:/gennavviewer.html?doc_id=0900253d800068ee&doc_header=terminal

[Banti]

Okay let's see...

Just because you have caller id, your trunk could use robbed bit to communicate to another trunk. ISDN is possible to setup if the trunk supports both ss7 and robbed bit. Since the ISDN signals are taken careof at the local switch. Some modems are better than others at accepting line noise and other handshaking problems. The robbed bit signal is modulated at the trunk so the modem only recieves an analog signal. Some modems are able to correct line noise and robbed bit problems SOMEtimes resemeble line noise...

Now, Certian modems do handle bit robbing better? I assume its a yes because when one always gets 26.4 on say an Acer56 and they put in a USR 56k they usually get better speeds.

The answer to this is both yes and no as per the above reasons.

I hope I have not confused the issue further. BTW where is here to you? I am in Metro Atlanta Area.

Banti

[Banti]

Sorry, about the a2d thing, misunderstood your statment. Since T1 communication was invented in the 60's ...most trunks use it. Actually if they have robbed bit (read digital) and/or ss7 (also read digital) chances are they are digital trunks... therefore they have no need to perform a d2a and a2d conversion on your dial up connection.

Banti