On Fri 12 Apr at 09:27 Peter Collis (3:713/914.16) wrote to Arthur Marsh:

 PC> While listening to Arthur Marsh Pete heard:What do you think 
 PC> of this line

 PC> G'day Arthur

 PC> ³ Speed                       16800 ³
 PC> ³ Symbol Rate             3429/3429 ³
 PC>  
 PC>  
 PC> So what do you think, wet string or what :-(

 AM> Wide bandwidth, low S/N ratio...

 PC> So why do i only get low connects, BTW the connect rate has 
 PC> fallen to about 14400 using the courier calling that system.

OK, to get a good symbol rate, you need a wide audio bandwidth (300-3400 Hz
with minimal roll-off). To get a good number of bits per symbol, you need a
good signal to noise ratio (e.g. 38 dB).

In your case you may have multiple PCM stages (Digital-Analogue-Digital
conversions). 16800 bps isn't that uncommon on international V.34 calls.

If the circuit has echo control devices not compliant with G.165 in it, all
bets are off /-:.

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