On Mon 30 Dec at 00:32 John Piper (3:712/841) wrote to All:

 JP> Ludi mentioned something about a post by Arthur which stated 
 JP> that there was a lack of suitable bandwith for V.34 modems 
 JP> on AXE (or was it S12?) exchanges. (Please elaborate or 
 JP> correct me, Arthur.) I will be ringing Telstra tomorrow 
 JP> (wish me luck) to find out what kind of exchange my 
 JP> line is connected to.

AXE to AXE connections with no local loop loss have 3 dB points at 3500 Hz
S12 to S12 connections with no local loop loss have 3 dB points at 3400 Hz

Therefore S12 gives less usable bandwidth, and is more likely not to
support the 3429 symbol rate.

to get 33600 bps from the 3429 symbol rate, you need very good signal to
noise performance.

 JP> atdt93890823
 JP> CONNECT 33600/ARQ/V34/LAPM/V42BIS

 JP> [Welcome screen and login prompt omitted.]

 JP> OK
 JP> ati6i11
 JP> USRobotics Courier HST Dual Standard V.34+ Fax Link 
 JP> Diagnostics...

 JP> [Some stats omitted; no block errors, link timeouts or link 
 JP> naks.]

 JP> Data Compression       V42BIS 2048/32
 JP> Equalization           Long
 JP> Fallback               Enabled
 JP> Protocol               LAPM 244/6
 JP> Speed                  33600/33600
 JP> Current Call           00:00:21

 JP> Online
 JP> USRobotics Courier HST Dual Standard V.34+ Fax Link 
 JP> Diagnostics...

 JP> Modulation               V.34+
 JP> Carrier Freq (Hz)        1959/1959
 JP> Symbol Rate              3429/3429
 JP> Trellis Code             64S-4D/16S-4D
 JP> Nonlinear Encoding       ON/ON
 JP> Precoding                ON/ON
 JP> Shaping                  OFF/ON
 JP> Preemphasis (-dB)        6/6
 JP> Recv/Xmit Level (-dB)    23/16
 JP> Roundtrip Delay (msec)   4

What was the S/N ratio reported?

Regards, Arthur.

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