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A more rational approach -- how I would like to change the cellphone industry.
Brenda Ann wrote:
"John Navas" wrote in message ... On Thu, 19 Jul 2007 18:43:58 -0700, Don Bowey wrote in : On 7/19/07 4:42 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 14:45:00 GMT, wrote in : In rec.radio.amateur.antenna Radium wrote: Digital cell phones should stop using the compression they use and start using monaural WMA compression with a CBR of 20 kbps or less and a sample rate of at least 44.1 KHz. In addition, the following must also apply: The audio bandwidth of the phone system is about 3 KHz. Actually more like 10 KHz. If he is commenting on the bandwidth of a message network channel/circuit, including cellular, it is about 3 kHz. Audio. Suggest you read more carefully. -- Best regards, FAQ FOR CINGULAR WIRELESS: John Navas http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ POTS phone lines are very limited. IIRC from my work with those systems, about 300-3600 Hz. Strictly human voice range, not meant for hi-fi. Special lines are still available for hi-fi use as audio STL's. I engineered a remote in Chicago a number of years ago, and the client wouldn't spring for ISDN, or equalized lines. ATT provided a POTS line and we got 8k analog audio out of it. Then again, we were next to an ATT store. Similar performance was observed at my condo in Heather Ridge. Here at the house, not two miles away, I'm lucky to hit 14.4 modem speeds, and 3k audio on a good day with my POTS line. Guaranteed performance, you're right, is only 300 to 3600Hz, and 14.4k modem speed. But real performance varies from company to company, CO to CO, line to line. And surprisingly good audio and high modem speeds, are possible with POTS technology. The instruments, themselves, are bandwidth limited. But the lines are often, but not always, much wider than the instrument. That's why, when addressing the phone with a hybrid, or repeating coil, directly, I have always been able to get passable audio on a POTS line. With AM audio bandwidth limited anyway, I could usually exceed the stations audio performance from the field and you couldn't tell we weren't using high performance lines. But that experience hasn't been limited to AM. I've been able, when lines were clean enough, to hit FM stations with audio wide enough, that the losses were ignorable. Hardly negligible, but certainly ignorable. And in at least two cases, better audio than was possible with Comrex, or with the POTS digital dialup systems out now. It just depends on who's providing the line, and how it's routed. BTW, equalized lines are being phased out. They're still available, but carriers are moving to make them prohibitively expensive to install and maintain, anymore, and carrier noise, which was never a problem before, is becoming a problem now. It's easier, more cost effective and requires less installer activity to drop in an ISDN line for broadcast. So carriers are really pushing that. Not that they're making it that much easier on the broadcaster. When I put in my ISDN link here at the house, I very nearly had to wire it for them. When the Florians owned WNIB, Bill got tired of all the carrier noise, and administrative crap that went along with his equalized studio-transmitter lines, and had ATT install a second set of control loops for his remote transmitter control. Control loops are copper, unequalized, and are designed to carry control voltages, down to DC and control databus output. They're basically just twisted pair. And dramatically less cost than broadcast lines. Bill got his own equalizers and set up his own equalized lines on the extra control loops and put his studio-transmitter audio there. It was the sweetest sounding audio on the dial. Right up there with WFMT, but less limiting. ATT threw a fit. Control loops are NOT for carrying program audio. Bill fought them on it. And never did return to ATT broadcast lines. He and Sonja eventually sold out to Bonneville for nearly a half a billion dollars. Sometimes the bear gets you, sometimes bear steaks are so tasty at the end of a long ride. |
A more rational approach -- how I would like to change the cell phone industry.
On Aug 16, 10:29 am, D Peter Maus wrote:
It's easier, more cost effective and requires less installer activity to drop in an ISDN line for broadcast. So carriers are really pushing that. Not that they're making it that much easier on the broadcaster. Wasn't there a rumor a couple years back that the phone companies are slowly discontinuing ISDN service? Or is that only for residential services as opposed to radio stations? Stephanie Weil New York City, USA |
A more rational approach -- how I would like to change the cellphone industry.
Stephanie Weil wrote:
On Aug 16, 10:29 am, D Peter Maus wrote: It's easier, more cost effective and requires less installer activity to drop in an ISDN line for broadcast. So carriers are really pushing that. Not that they're making it that much easier on the broadcaster. Wasn't there a rumor a couple years back that the phone companies are slowly discontinuing ISDN service? Or is that only for residential services as opposed to radio stations? Stephanie Weil New York City, USA They don't want to do ISDN internet services, anymore. But I'm using ISDN as a studio-studio link. So far, no one has suggested to me that it's not going to continue. |
A more rational approach -- how I would like to change thecell...
John Smith 1 reported Radium to write:
"Analog cell phones shoild stop using FM and should start using AM at whatever practical radio frequency available." Tune the FM band. Recovered audio is all about the same loudness. Tune across the AM band. Even with stromg AVC action, loudness varies with signal strength. Loudness independent of carrier signal strength is a great advantage of FM. Amateur FM repeaters allow hand helds with a few milliwatts output sound about as loud as a base station with maximum allowed power output. Imagine a cell phone in all the disadvantaged locations it encounteres as it switches from repeater to repeater along its route. Loudness would be nightmareish. Radium`s proposal won`t be satisfactory with analog phones. Best regards, Richard Harrison, KB5WZI |
A more rational approach -- how I would like to change thecell phone industry.
On 8/16/07 7:29 AM, in article
, "D Peter Maus" wrote: Brenda Ann wrote: "John Navas" wrote in message ... On Thu, 19 Jul 2007 18:43:58 -0700, Don Bowey wrote in : On 7/19/07 4:42 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 14:45:00 GMT, wrote in : In rec.radio.amateur.antenna Radium wrote: Digital cell phones should stop using the compression they use and start using monaural WMA compression with a CBR of 20 kbps or less and a sample rate of at least 44.1 KHz. In addition, the following must also apply: The audio bandwidth of the phone system is about 3 KHz. Actually more like 10 KHz. If he is commenting on the bandwidth of a message network channel/circuit, including cellular, it is about 3 kHz. Audio. Suggest you read more carefully. -- Best regards, FAQ FOR CINGULAR WIRELESS: John Navas http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ POTS phone lines are very limited. IIRC from my work with those systems, about 300-3600 Hz. Strictly human voice range, not meant for hi-fi. Special lines are still available for hi-fi use as audio STL's. I engineered a remote in Chicago a number of years ago, and the client wouldn't spring for ISDN, or equalized lines. ATT provided a POTS line and we got 8k analog audio out of it. Then again, we were next to an ATT store. Similar performance was observed at my condo in Heather Ridge. Here at the house, not two miles away, I'm lucky to hit 14.4 modem speeds, and 3k audio on a good day with my POTS line. Guaranteed performance, you're right, is only 300 to 3600Hz, I can't think of even one US Telco that would (or could) guarantee that for a POTS line. and 14.4k modem speed. But real performance varies from company to company, CO to CO, line to line. And surprisingly good audio and high modem speeds, are possible with POTS technology. The instruments, themselves, are bandwidth limited. But the lines are often, but not always, much wider than the instrument. That's why, when addressing the phone with a hybrid, or repeating coil, directly, I have always been able to get passable audio on a POTS line. With AM audio bandwidth limited anyway, I could usually exceed the stations audio performance from the field and you couldn't tell we weren't using high performance lines. But that experience hasn't been limited to AM. I've been able, when lines were clean enough, to hit FM stations with audio wide enough, that the losses were ignorable. Hardly negligible, but certainly ignorable. And in at least two cases, better audio than was possible with Comrex, or with the POTS digital dialup systems out now. It just depends on who's providing the line, and how it's routed. BTW, equalized lines are being phased out. They're still available, but carriers are moving to make them prohibitively expensive to install and maintain, anymore, and carrier noise, which was never a problem before, is becoming a problem now. It's easier, more cost effective and requires less installer activity to drop in an ISDN line for broadcast. So carriers are really pushing that. Not that they're making it that much easier on the broadcaster. When I put in my ISDN link here at the house, I very nearly had to wire it for them. When the Florians owned WNIB, Bill got tired of all the carrier noise, and administrative crap that went along with his equalized studio-transmitter lines, and had ATT install a second set of control loops for his remote transmitter control. Control loops are copper, unequalized, and are designed to carry control voltages, down to DC and control databus output. They're basically just twisted pair. And dramatically less cost than broadcast lines. Bill got his own equalizers and set up his own equalized lines on the extra control loops and put his studio-transmitter audio there. It was the sweetest sounding audio on the dial. Right up there with WFMT, but less limiting. ATT threw a fit. Control loops are NOT for carrying program audio. Bill fought them on it. And never did return to ATT broadcast lines. He and Sonja eventually sold out to Bonneville for nearly a half a billion dollars. AT&T didn't sell local channels. What Telco are you calling AT&T? Sometimes the bear gets you, sometimes bear steaks are so tasty at the end of a long ride. |
A more rational approach -- how I would like to change the cellphone industry.
Don Bowey wrote:
On 8/16/07 7:29 AM, in article , "D Peter Maus" wrote: Brenda Ann wrote: "John Navas" wrote in message ... On Thu, 19 Jul 2007 18:43:58 -0700, Don Bowey wrote in : On 7/19/07 4:42 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 14:45:00 GMT, wrote in : In rec.radio.amateur.antenna Radium wrote: Digital cell phones should stop using the compression they use and start using monaural WMA compression with a CBR of 20 kbps or less and a sample rate of at least 44.1 KHz. In addition, the following must also apply: The audio bandwidth of the phone system is about 3 KHz. Actually more like 10 KHz. If he is commenting on the bandwidth of a message network channel/circuit, including cellular, it is about 3 kHz. Audio. Suggest you read more carefully. -- Best regards, FAQ FOR CINGULAR WIRELESS: John Navas http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ POTS phone lines are very limited. IIRC from my work with those systems, about 300-3600 Hz. Strictly human voice range, not meant for hi-fi. Special lines are still available for hi-fi use as audio STL's. I engineered a remote in Chicago a number of years ago, and the client wouldn't spring for ISDN, or equalized lines. ATT provided a POTS line and we got 8k analog audio out of it. Then again, we were next to an ATT store. Similar performance was observed at my condo in Heather Ridge. Here at the house, not two miles away, I'm lucky to hit 14.4 modem speeds, and 3k audio on a good day with my POTS line. Guaranteed performance, you're right, is only 300 to 3600Hz, I can't think of even one US Telco that would (or could) guarantee that for a POTS line. ATT does. So does Verizon. And GTE,...at least before they became Sprint. If you don't meet those figures, you can complain. They'll move on it. It's part of the tariff structure. I spent a number of years at working with Telcos on just this matter. and 14.4k modem speed. But real performance varies from company to company, CO to CO, line to line. And surprisingly good audio and high modem speeds, are possible with POTS technology. The instruments, themselves, are bandwidth limited. But the lines are often, but not always, much wider than the instrument. That's why, when addressing the phone with a hybrid, or repeating coil, directly, I have always been able to get passable audio on a POTS line. With AM audio bandwidth limited anyway, I could usually exceed the stations audio performance from the field and you couldn't tell we weren't using high performance lines. But that experience hasn't been limited to AM. I've been able, when lines were clean enough, to hit FM stations with audio wide enough, that the losses were ignorable. Hardly negligible, but certainly ignorable. And in at least two cases, better audio than was possible with Comrex, or with the POTS digital dialup systems out now. It just depends on who's providing the line, and how it's routed. BTW, equalized lines are being phased out. They're still available, but carriers are moving to make them prohibitively expensive to install and maintain, anymore, and carrier noise, which was never a problem before, is becoming a problem now. It's easier, more cost effective and requires less installer activity to drop in an ISDN line for broadcast. So carriers are really pushing that. Not that they're making it that much easier on the broadcaster. When I put in my ISDN link here at the house, I very nearly had to wire it for them. When the Florians owned WNIB, Bill got tired of all the carrier noise, and administrative crap that went along with his equalized studio-transmitter lines, and had ATT install a second set of control loops for his remote transmitter control. Control loops are copper, unequalized, and are designed to carry control voltages, down to DC and control databus output. They're basically just twisted pair. And dramatically less cost than broadcast lines. Bill got his own equalizers and set up his own equalized lines on the extra control loops and put his studio-transmitter audio there. It was the sweetest sounding audio on the dial. Right up there with WFMT, but less limiting. ATT threw a fit. Control loops are NOT for carrying program audio. Bill fought them on it. And never did return to ATT broadcast lines. He and Sonja eventually sold out to Bonneville for nearly a half a billion dollars. AT&T didn't sell local channels. What Telco are you calling AT&T? Sometimes the bear gets you, sometimes bear steaks are so tasty at the end of a long ride. |
A more rational approach -- how I would like to change the cell phone industry.
On Aug 16, 4:29 am, "Brenda Ann" wrote:
"John Navas" wrote in message ... On Thu, 19 Jul 2007 18:43:58 -0700, Don Bowey wrote in : On 7/19/07 4:42 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 14:45:00 GMT, wrote in : In rec.radio.amateur.antenna Radium wrote: Digital cell phones should stop using the compression they use and start using monaural WMA compression with a CBR of 20 kbps or less and a sample rate of at least 44.1 KHz. In addition, the following must also apply: The audio bandwidth of the phone system is about 3 KHz. Actually more like 10 KHz. If he is commenting on the bandwidth of a message network channel/circuit, including cellular, it is about 3 kHz. Audio. Suggest you read more carefully. -- Best regards, FAQ FOR CINGULAR WIRELESS: John Navas http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ POTS phone lines are very limited. IIRC from my work with those systems, about 300-3600 Hz. Strictly human voice range, not meant for hi-fi. Special lines are still available for hi-fi use as audio STL's ? "STL's" ? |
A more rational approach -- how I would like to change the cellphone industry.
RHF wrote:
On Aug 16, 4:29 am, "Brenda Ann" wrote: "John Navas" wrote in message ... On Thu, 19 Jul 2007 18:43:58 -0700, Don Bowey wrote in : On 7/19/07 4:42 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 14:45:00 GMT, wrote in : In rec.radio.amateur.antenna Radium wrote: Digital cell phones should stop using the compression they use and start using monaural WMA compression with a CBR of 20 kbps or less and a sample rate of at least 44.1 KHz. In addition, the following must also apply: The audio bandwidth of the phone system is about 3 KHz. Actually more like 10 KHz. If he is commenting on the bandwidth of a message network channel/circuit, including cellular, it is about 3 kHz. Audio. Suggest you read more carefully. -- Best regards, FAQ FOR CINGULAR WIRELESS: John Navas http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ POTS phone lines are very limited. IIRC from my work with those systems, about 300-3600 Hz. Strictly human voice range, not meant for hi-fi. Special lines are still available for hi-fi use as audio STL's ? "STL's" ? Studio to Transmitter Link. |
A more rational approach -- how I would like to change the cell phone industry.
On Thu, 16 Aug 2007 11:29:19 -0700, Don Bowey wrote
in : On 8/16/07 7:29 AM, in article , "D Peter Maus" wrote: Guaranteed performance, you're right, is only 300 to 3600Hz, I can't think of even one US Telco that would (or could) guarantee that for a POTS line. Check the spec. -- Best regards, FAQ FOR CINGULAR WIRELESS: John Navas http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ |
A more rational approach -- how I would like to change the cell phone industry.
On Thu, 16 Aug 2007 20:29:12 +0900, "Brenda Ann"
wrote in : "John Navas" wrote in message .. . On Thu, 19 Jul 2007 18:43:58 -0700, Don Bowey wrote in : On 7/19/07 4:42 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 14:45:00 GMT, wrote in : In rec.radio.amateur.antenna Radium wrote: Digital cell phones should stop using the compression they use and start using monaural WMA compression with a CBR of 20 kbps or less and a sample rate of at least 44.1 KHz. In addition, the following must also apply: The audio bandwidth of the phone system is about 3 KHz. Actually more like 10 KHz. If he is commenting on the bandwidth of a message network channel/circuit, including cellular, it is about 3 kHz. Audio. Suggest you read more carefully. POTS phone lines are very limited. IIRC from my work with those systems, about 300-3600 Hz. Strictly human voice range, not meant for hi-fi. Special lines are still available for hi-fi use as audio STL's. POTS lines are encoded at 64 Kbps, which is why V.90 modems work, and which is sufficient for decent audio, albeit not "hi-fi". -- Best regards, FAQ FOR CINGULAR WIRELESS: John Navas http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ |
A more rational approach -- how I would like to change the cell phone industry.
On Aug 26, 7:15 pm, John Navas wrote:
On Thu, 16 Aug 2007 06:52:55 -0700, Don Bowey wrote in : On 8/15/07 11:07 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 18:43:58 -0700, Don Bowey wrote in : On 7/19/07 4:42 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 14:45:00 GMT, wrote in : In rec.radio.amateur.antenna Radium wrote: Digital cell phones should stop using the compression they use and start using monaural WMA compression with a CBR of 20 kbps or less and a sample rate of at least 44.1 KHz. In addition, the following must also apply: The audio bandwidth of the phone system is about 3 KHz. Actually more like 10 KHz. If he is commenting on the bandwidth of a message network channel/circuit, including cellular, it is about 3 kHz. Audio. Suggest you read more carefully. Audio WHAT? Read what more carefully? Are you attempting to say the audio bandwidth of a message network channel is greater than about 3 kHz? No. Suggest you read more carefully. -- Best regards, FAQ FOR CINGULAR WIRELESS: John Navas http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ- Hide quoted text - - Show quoted text - Read More... Doh! C a r e f u l l y . . . D O H ! |
A more rational approach -- how I would like to change the cell phone industry.
"John Navas" wrote in message ... POTS phone lines are very limited. IIRC from my work with those systems, about 300-3600 Hz. Strictly human voice range, not meant for hi-fi. Special lines are still available for hi-fi use as audio STL's. POTS lines are encoded at 64 Kbps, which is why V.90 modems work, and which is sufficient for decent audio, albeit not "hi-fi". POTS lines are not encoded at all. Hence "Plain Old Telephone Service" which can be used with any telephone (ain't no decoders in a WE 500 deskset) that uses a DC line. |
A more rational approach -- how I would like to change the cell phone industry.
On Aug 26, 8:44 pm, "Brenda Ann" wrote:
"John Navas" wrote in message ... POTS phone lines are very limited. IIRC from my work with those systems, about 300-3600 Hz. Strictly human voice range, not meant for hi-fi. Special lines are still available for hi-fi use as audio STL's. POTS lines are encoded at 64 Kbps, which is why V.90 modems work, and which is sufficient for decent audio, albeit not "hi-fi". POTS lines are not encoded at all. Hence "Plain Old Telephone Service" which can be used with any telephone (ain't no decoders in a WE 500 deskset) that uses a DC line. POTS de PANS . . . DOH ! |
A more rational approach -- how I would like to change the cellphone industry.
Brenda Ann wrote:
"John Navas" wrote in message ... POTS phone lines are very limited. IIRC from my work with those systems, about 300-3600 Hz. Strictly human voice range, not meant for hi-fi. Special lines are still available for hi-fi use as audio STL's. POTS lines are encoded at 64 Kbps, which is why V.90 modems work, and which is sufficient for decent audio, albeit not "hi-fi". POTS lines are not encoded at all. Hence "Plain Old Telephone Service" which can be used with any telephone (ain't no decoders in a WE 500 deskset) that uses a DC line. In the US, the telephone network has been digital since 1962. At the time of the conversion, there was a decision made to keep the instrument and the interface familiar to the user, so there is no conversion in the deskset, and the 'last mile' from the CO is still analogue with battery voltage as it always has been. But behind that interface, the network is digital. Now, that 'last mile' analogue circuit can be VERY poor. In my area, a v.92 modem will only pass 14.4. While only a mile up the road, I was getting 53k+ on the same v.92 modem. When the network was converted from analogue to digital, there were complaints that voices no longer sounded right and that some people didn't sound like themselves. The complaints reached suce a pitch that AT&T launched a PR campaign in which TV spots attempted to explain the change in the audio at the instrument. As was the style of the times, they didn't really explain anything, certainly nothing as technical as digital audio, but instead, they described, through narrative and animation, how a person speaking into a telephone would connect to the central hub, where a voice that was similar to the speaker's voice was selected, and sent on to the far end. That's why someone didn't sound like themeselves. No one bought it, of course, what with AT&T's reputation, by that point...but it was a hilarious exercise in TelCo spin. And paved the way for the explanation of 'Tru-Voice' 30 years later. Yes, POTS lines are encoded. At the CO. The only thing POTS about a POTS line is what sits on your desk, and a length of copper to the network. |
A more rational approach -- how I would like to change thecell phone industry.
|
A more rational approach -- how I would like to change thecell phone industry.
On 8/26/07 7:15 PM, in article ,
"John Navas" wrote: On Thu, 16 Aug 2007 06:52:55 -0700, Don Bowey wrote in : On 8/15/07 11:07 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 18:43:58 -0700, Don Bowey wrote in : On 7/19/07 4:42 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 14:45:00 GMT, wrote in : In rec.radio.amateur.antenna Radium wrote: Digital cell phones should stop using the compression they use and start using monaural WMA compression with a CBR of 20 kbps or less and a sample rate of at least 44.1 KHz. In addition, the following must also apply: The audio bandwidth of the phone system is about 3 KHz. Actually more like 10 KHz. If he is commenting on the bandwidth of a message network channel/circuit, including cellular, it is about 3 kHz. Audio. Suggest you read more carefully. Audio WHAT? Read what more carefully? Are you attempting to say the audio bandwidth of a message network channel is greater than about 3 kHz? No. Suggest you read more carefully. Suggest you kiss my ass. |
A more rational approach -- how I would like to change thecell phone industry.
On 8/26/07 7:31 PM, in article ,
"John Navas" wrote: On Thu, 16 Aug 2007 20:29:12 +0900, "Brenda Ann" wrote in : "John Navas" wrote in message ... On Thu, 19 Jul 2007 18:43:58 -0700, Don Bowey wrote in : On 7/19/07 4:42 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 14:45:00 GMT, wrote in : In rec.radio.amateur.antenna Radium wrote: Digital cell phones should stop using the compression they use and start using monaural WMA compression with a CBR of 20 kbps or less and a sample rate of at least 44.1 KHz. In addition, the following must also apply: The audio bandwidth of the phone system is about 3 KHz. Actually more like 10 KHz. If he is commenting on the bandwidth of a message network channel/circuit, including cellular, it is about 3 kHz. Audio. Suggest you read more carefully. POTS phone lines are very limited. IIRC from my work with those systems, about 300-3600 Hz. Strictly human voice range, not meant for hi-fi. Special lines are still available for hi-fi use as audio STL's. POTS lines are encoded at 64 Kbps, which is why V.90 modems work, and which is sufficient for decent audio, albeit not "hi-fi". Having said that, you have said nothing useful. |
A more rational approach -- how I would like to change thecell phone industry.
|
A more rational approach -- how I would like to change thecell phone industry.
On 8/26/07 9:21 PM, in article
, "D Peter Maus" wrote: Brenda Ann wrote: "John Navas" wrote in message ... POTS phone lines are very limited. IIRC from my work with those systems, about 300-3600 Hz. Strictly human voice range, not meant for hi-fi. Special lines are still available for hi-fi use as audio STL's. POTS lines are encoded at 64 Kbps, which is why V.90 modems work, and which is sufficient for decent audio, albeit not "hi-fi". POTS lines are not encoded at all. Hence "Plain Old Telephone Service" which can be used with any telephone (ain't no decoders in a WE 500 deskset) that uses a DC line. In the US, the telephone network has been digital since 1962. At the time of the conversion, there was a decision made to keep the instrument and the interface familiar to the user, so there is no conversion in the deskset, and the 'last mile' from the CO is still analogue with battery voltage as it always has been. But behind that interface, the network is digital. Now, that 'last mile' analogue circuit can be VERY poor. In my area, a v.92 modem will only pass 14.4. While only a mile up the road, I was getting 53k+ on the same v.92 modem. When the network was converted from analogue to digital, there were complaints that voices no longer sounded right and that some people didn't sound like themselves. The complaints reached suce a pitch that AT&T launched a PR campaign in which TV spots attempted to explain the change in the audio at the instrument. As was the style of the times, they didn't really explain anything, certainly nothing as technical as digital audio, but instead, they described, through narrative and animation, how a person speaking into a telephone would connect to the central hub, where a voice that was similar to the speaker's voice was selected, and sent on to the far end. That's why someone didn't sound like themeselves. No one bought it, of course, what with AT&T's reputation, by that point...but it was a hilarious exercise in TelCo spin. And paved the way for the explanation of 'Tru-Voice' 30 years later. Yes, POTS lines are encoded. At the CO. The only thing POTS about a POTS line is what sits on your desk, and a length of copper to the network. You ignored pair-gain multiplexing in the Exchange Plant, which uses the same codecs as are used in the message network. |
A more rational approach -- how I would like to change the cellphone industry.
Don Bowey wrote:
On 8/26/07 9:21 PM, in article , "D Peter Maus" wrote: Brenda Ann wrote: "John Navas" wrote in message ... POTS phone lines are very limited. IIRC from my work with those systems, about 300-3600 Hz. Strictly human voice range, not meant for hi-fi. Special lines are still available for hi-fi use as audio STL's. POTS lines are encoded at 64 Kbps, which is why V.90 modems work, and which is sufficient for decent audio, albeit not "hi-fi". POTS lines are not encoded at all. Hence "Plain Old Telephone Service" which can be used with any telephone (ain't no decoders in a WE 500 deskset) that uses a DC line. In the US, the telephone network has been digital since 1962. At the time of the conversion, there was a decision made to keep the instrument and the interface familiar to the user, so there is no conversion in the deskset, and the 'last mile' from the CO is still analogue with battery voltage as it always has been. But behind that interface, the network is digital. Now, that 'last mile' analogue circuit can be VERY poor. In my area, a v.92 modem will only pass 14.4. While only a mile up the road, I was getting 53k+ on the same v.92 modem. When the network was converted from analogue to digital, there were complaints that voices no longer sounded right and that some people didn't sound like themselves. The complaints reached suce a pitch that AT&T launched a PR campaign in which TV spots attempted to explain the change in the audio at the instrument. As was the style of the times, they didn't really explain anything, certainly nothing as technical as digital audio, but instead, they described, through narrative and animation, how a person speaking into a telephone would connect to the central hub, where a voice that was similar to the speaker's voice was selected, and sent on to the far end. That's why someone didn't sound like themeselves. No one bought it, of course, what with AT&T's reputation, by that point...but it was a hilarious exercise in TelCo spin. And paved the way for the explanation of 'Tru-Voice' 30 years later. Yes, POTS lines are encoded. At the CO. The only thing POTS about a POTS line is what sits on your desk, and a length of copper to the network. You ignored pair-gain multiplexing in the Exchange Plant, which uses the same codecs as are used in the message network. Um.....no, actually, I didn't. |
A more rational approach -- how I would like to change thecell phone industry.
On 8/27/07 8:18 AM, in article
, "D Peter Maus" wrote: At the CO. How about the one at the pair-gain terminal that you forgot? |
A more rational approach -- how I would like to change the cell phone industry.
In article ,
"Brenda Ann" wrote: "John Navas" wrote in message ... Snip John Navas is a notorious Troll in many news groups. Please do not respond to him in re.radio.shortwave. -- Telamon Ventura, California |
A more rational approach -- how I would like to change the cell phone industry.
In article ,
Don Bowey wrote: On 8/26/07 7:15 PM, in article , "John Navas" wrote: On Thu, 16 Aug 2007 06:52:55 -0700, Don Bowey wrote in : On 8/15/07 11:07 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 18:43:58 -0700, Don Bowey wrote in : On 7/19/07 4:42 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 14:45:00 GMT, wrote in : In rec.radio.amateur.antenna Radium wrote: Digital cell phones should stop using the compression they use and start using monaural WMA compression with a CBR of 20 kbps or less and a sample rate of at least 44.1 KHz. In addition, the following must also apply: The audio bandwidth of the phone system is about 3 KHz. Actually more like 10 KHz. If he is commenting on the bandwidth of a message network channel/circuit, including cellular, it is about 3 kHz. Audio. Suggest you read more carefully. Audio WHAT? Read what more carefully? Are you attempting to say the audio bandwidth of a message network channel is greater than about 3 kHz? No. Suggest you read more carefully. Suggest you kiss my ass. I suggest you pay attention to the news groups to which you cross post. Plonk -- Telamon Ventura, California |
A more rational approach -- how I would like to change thecell phone industry.
On 9/1/07 10:48 AM, in article
, "Telamon" wrote: In article , Don Bowey wrote: On 8/26/07 7:15 PM, in article , "John Navas" wrote: On Thu, 16 Aug 2007 06:52:55 -0700, Don Bowey wrote in : On 8/15/07 11:07 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 18:43:58 -0700, Don Bowey wrote in : On 7/19/07 4:42 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 14:45:00 GMT, wrote in : In rec.radio.amateur.antenna Radium wrote: Digital cell phones should stop using the compression they use and start using monaural WMA compression with a CBR of 20 kbps or less and a sample rate of at least 44.1 KHz. In addition, the following must also apply: The audio bandwidth of the phone system is about 3 KHz. Actually more like 10 KHz. If he is commenting on the bandwidth of a message network channel/circuit, including cellular, it is about 3 kHz. Audio. Suggest you read more carefully. Audio WHAT? Read what more carefully? Are you attempting to say the audio bandwidth of a message network channel is greater than about 3 kHz? No. Suggest you read more carefully. Suggest you kiss my ass. I suggest you pay attention to the news groups to which you cross post. Plonk Idiot. The reply goes to whatever distribution was set on the posted message. Plonk yourself, Troll. |
A more rational approach -- how I would like to change the cell phone industry.
On Sep 1, 10:45 am, Telamon
wrote: In article , "Brenda Ann" wrote: "John Navas" wrote in message .. . Snip - John Navas is a notorious Troll in many news groups. - Please do not respond to him in re.radio.shortwave. - - -- - Telamon - Ventura, California Telamon - Was 'that' an Oops ? ;-} {Please do not respond to him in re.radio.shortwave.} DOH ! - Oops It Was For Me Too ! :o) ~ RHF |
A more rational approach -- how I would like to change the cell phone industry.
On Sep 1, 10:48 am, Telamon
wrote: In article , Don Bowey wrote: On 8/26/07 7:15 PM, in article , "John Navas" wrote: On Thu, 16 Aug 2007 06:52:55 -0700, Don Bowey wrote in : On 8/15/07 11:07 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 18:43:58 -0700, Don Bowey wrote in : On 7/19/07 4:42 PM, in article , "John Navas" wrote: On Thu, 19 Jul 2007 14:45:00 GMT, wrote in : In rec.radio.amateur.antenna Radium wrote: Digital cell phones should stop using the compression they use and start using monaural WMA compression with a CBR of 20 kbps or less and a sample rate of at least 44.1 KHz. In addition, the following must also apply: The audio bandwidth of the phone system is about 3 KHz. Actually more like 10 KHz. If he is commenting on the bandwidth of a message network channel/circuit, including cellular, it is about 3 kHz. Audio. Suggest you read more carefully. Audio WHAT? Read what more carefully? Are you attempting to say the audio bandwidth of a message network channel is greater than about 3 kHz? No. Suggest you read more carefully. Suggest you kiss my ass. - I suggest you pay attention to the news groups to which you cross post. - - Plonk - - -- - Telamon - Ventura, California Telamon - Was 'that' an Oops ? ;-} { I suggest you pay attention to the news groups to which you cross post.} sci.electronics.basics, rec.radio.shortwave, rec.radio.amateur.antenna, alt.cellular.cingular, alt.internet.wireless DOH ! - Oops It Was For Me Too ! :o) ~ RHF |
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