Voiceband Modem Standards      
         
 
CCITT Standart
Data Rate
Full/Half-duplex
Channel Separation
Carrier Frecuency (Hz)
Modulation Method
Modulation Rate (Baud)
Bits Encoded

Synchronous/
Asynchronous

Back Channel
GSTN
Leased Lines
Equalization
Scrambler
v.21
300
Full
Frequency Division
1080 & 1750
FSK
300
1:1
Either
Not Defined
Yes
No
Not Defined
Not Defined
v.22
1200
Full
Frequency Division
1200 & 2400
PSK
600
2:1
Either
Not Defined
Yes
Point-to-Point 2-Wire
Fixed
Yes
v.22
600
Full
Frequency Division
1200 & 2400
PSK
600
1:1
Either
Not Defined
Yes
Point-to-Point 2-Wire
Fixed
Yes
v.22bis
2400
Full
Frequency Division
1200 & 2400
QAM
600
4:1
Either
Not Defined
Yes
Point-to-Point 2-Wire
Fixed/
Adaptative
Yes
v.23
600(1)
Half
N/A
1300 & 1700
FM
600
N/A
Either
Yes
Yes
No
Not Defined
Not Defined
v.23
1200(1)
Half
N/A
1300 & 2100
FM
1200
N/A
Either
Yes
Yes
No
Not Defined
Not Defined
v.25
2400
Full
4-Wire
1800
PSK
1200
2:1
Synchronous
Yes
No
Point-to-Point
Multipoint
2-Wire
Not Defined
Not Defined
v.26bis
2400
Half
N/A
1800
PSK
1200
2:1
Synchronous
Yes
Yes
No
Fixed
Not Defined
v.26bis
1200
Half
N/A
1800
PSK
1200
1:1
Synchronous
Yes
Yes
No
Fixed
Not Defined
v.26ter
2400
Either
Echo Cancellation
1800
PSK
1200
2:1
Either
Not Defined
Yes
Point-to-Point 2-Wire
Either
Yes
v.26ter
1200
Either
Echo Cancellation
1800
PSK
1200
1:1
Either
Not Defined
Yes
Point-to-Point 2-Wire
Either
Yes
v.27
4800
Either
ND (3)
1800
PSK
1600
3:1
Synchronous
Yes
No
Yes (Assumed)
Manual
Yes
v.27bis
4800
Either
4-Wire (4)
1800
PSK
1600
3:1
Synchronous
Yes
No
2-Wire
4-Wire
Adaptative
Yes

v.27bis

2400
Either
4-Wire (4)
1800
PSK
1200
2:1
Synchronous
Yes
No
2-Wire
4-Wire
Adaptative
Yes
v.27ter
4800
Half
None
1800
PSK
1800
3:1
Synchronous
Yes
Yes
No
Adaptative
Yes
v.27ter
2400
Half
None
1800
PSK
1200
2:1
Synchronous
Yes
Yes
No
Adaptative
Yes
v.29
9600
Either
4-Wire
1700
QAM
2400
4:1
Synchronous
No
No
Point-to-Point 4-Wire
Adaptative
Yes
v.29
7200
Either
4-Wire
1700
PSK(5)
2400
3:1
Synchronous
Not Defined
No
Point-to-Point 4-Wire
Adaptative
Yes
v.29
4800
Either
4-Wire
1700
PSK(5)
2400
2:1
Synchronous
Not Defined
No
Point-to-Point 4-Wire
Adaptative
Yes
v.32
9600
Full
Echo Cancellation
1800
QAM
2400
4:1
Synchronous
Not Defined
Yes
Point-to-Point 2-Wire
Adaptative
Yes
v.32bis
14400
Full
Echo Cancellation
1800
Mod. Trellis
2400
6:1
Synchronous
Not Defined
Yes
Point-to-Point 2-Wire
Adaptative
Yes
v.32
9600
Full
Echo Cancellation
1800
QAM
2400
4:1
Synchronous
Not Defined
Yes
Point-to-Point 2-Wire
Adaptative
Yes
v.32
4800
Full
Echo Cancellation
1800
QAM
2400
2:1
Synchronous
Not Defined
Yes
Point-to-Point 2-Wire
Adaptative
Yes
v.33
14400
Half
Synchronous
Not Defined
Yes
Adaptative
Yes
v.34
28800
Full
Echo Cancellation
1800
Mod. Trellis
2400
12:1
Synchronous
Not Defined
Yes
Point-to-Point 2-Wire
Not Defined
Yes
     
         
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CCITT Standart
Data Rate
Full/Half-duplex
Channel Separation
Carrier Frecuency (Hz)
Modulation Method
Modulation Rate (Baud)
Bits Encoded

Synchronous/
Asynchronous

Back Channel
GSTN
Leased Lines
Equalization
Scrambler
103
300
Full
Frequency Division
2225 & 1720(m)
2025 & 1070 (s)
FSK
300
1:1
Either
No
Yes
No
Fixed
No
201
2400
Half
None
1800
PSK
1200
2:1
Synchronous
No
Yes
Point-to-Point 2-Wire
Adaptative
Yes
202
1200
Half
None
1200 & 2200
FSK
1200
1:1
Either
Yes
Yes
Point-to-Point 2-Wire
Fixed
No
208
4800
Half
None
1800
QAM
1600
3:1
Synchronous
No
Yes

Point-to-Point 2-Wire

Adaptative
Yes
212
1200
Full
Frequency Division
1200 & 2400
PSK
600
2:1
Either
No
Yes
No
Fixed
Yes
     
         
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