Talk:Bell 202 modem: Difference between revisions
→full duplex: new section |
|||
Line 30: | Line 30: | ||
I removed |
I removed |
||
:and at a rate of 1800 bits per second [[Duplex (telecommunications)#Full-duplex|full duplex]] |
:and at a rate of 1800 bits per second [[Duplex (telecommunications)#Full-duplex|full duplex]] |
||
from the lede since Bell 202 is half-duplex I'm quite sure. An 1800 bps full duplex modem with that sort of modulation would not have been possible on a phone line. I believe the |
from the lede since Bell 202 is half-duplex I'm quite sure. An 1800 bps full duplex modem with that sort of modulation would not have been possible on a phone line, at least with technology of the era. I believe the scheme could do 1800 bps half duplex in principle, but was usually used at 1200. There was (I think) a reverse channel that someone might have confused with full duplex, but it was at very low speed, like 5 bps. The idea was you could use it to send a "break" signal to tell the other end to stop sending and switch to receive mode. I'm sure the specs for this are still around. |
||
AX.25 uses the same audio frequencies as Bell 202 but in other regards is completely different (signalling, frame formats etc). |
AX.25 uses the same audio frequencies as Bell 202 but in other regards is completely different (signalling, frame formats etc). |
Revision as of 19:46, 1 June 2012
Computing Unassessed | ||||||||||
|
Details of the modulation technique (frequencies, etc.) would be useful here.
I know the Bell 202 supported several different operating modes, including an asymmetrical one where upstream data was sent at (I think) 75 bps. Unfortunately, I haven't found a reliable source for this information.
Simon 15:44, 20 Jan 2005 (UTC)
Also, should this article be included in the Telecommunications history category, like Bell 103 modem?
Simon 15:23, 31 Jan 2005 (UTC)
APRS acronym
According to the creator of APRS, APRS stands for Automatic Packet Reporting System and not Automatic Postion Reporting System, see Bob Bruninga, WB4APR 's web site.
Mikelachaine (talk) 15:55, 29 February 2008 (UTC)
AFSK acronym
Surely AFSK would properly stand for "Amplitude Frequency Shift Keying", not "Audio Frequency Shift Keying". If it is "Audio ...", then this should be well noted. —Preceding unsigned comment added by 203.184.50.47 (talk) 02:19, 26 October 2010 (UTC)
Incongruencies on this article
In North America (and perhaps elsewhere) <--- perhaps? where?
The modified Bell 202 AFSK modulation, AX.25, <--- AX.25 is a data link layer protocol, and has nothing to do with FSK modulation — Preceding unsigned comment added by 212.170.101.99 (talk) 20:09, 21 June 2011 (UTC)
full duplex
I removed
- and at a rate of 1800 bits per second full duplex
from the lede since Bell 202 is half-duplex I'm quite sure. An 1800 bps full duplex modem with that sort of modulation would not have been possible on a phone line, at least with technology of the era. I believe the scheme could do 1800 bps half duplex in principle, but was usually used at 1200. There was (I think) a reverse channel that someone might have confused with full duplex, but it was at very low speed, like 5 bps. The idea was you could use it to send a "break" signal to tell the other end to stop sending and switch to receive mode. I'm sure the specs for this are still around.
AX.25 uses the same audio frequencies as Bell 202 but in other regards is completely different (signalling, frame formats etc).