From: madsere@okys.infoserv.com (Rene Madsen)
Newsgroups: comp.dcom.modems
Subject: BocaModem settings
Keywords: Manual not clear ...
Date: 7 Oct 92 16:38:08 GMT
Organization: Brackton Ltd. Luxembourg


Hi Netters,

I have the BocaModem 14400 internal which in general works ok. Only, I'd
like to be sure of the following:

1.	I want connections initiated WITH V.42 LAPM error correction.
	I DON'T want the alternative V.42 MNP-4 error correction.

2.	I DON'T want V.42bis or MNP-5 compression,

3.	I want the connection to use V.32bis (14400 bps) whenever 
	possible, and retrain the line when necessary.

Now this would'nt be a problem if the manual was readable (but as y'all 
know, the Boca manual leaves much to be desired). My question is therefore
to anyone having the necessary understanding of modem operation to deduct
the correct answers out of a lousy manual...

In other words, I'm after getting PROTOCOL LAPM,  COMPRESSION NONE. 
So far all I have managed is to get either PROTOCOL NONE or PROTOCOL
MNP, COMPRESSION NONE.  (I've set S95=42 to get feedback on the actual
connection.)

Below are my current modem settings:

ACTIVE PROFILE:
B1 E0 L0 M0 N1 P Q0 V1 W0 X4 Y0 &C1 &D3 &G0 &J0 &K3 &Q5 &R0 &S1 &T4 &X0 &Y0
S00:001 S01:000 S02:043 S03:013 S04:010 S05:008 S06:002 S07:050 S08:002 S09:005
S10:000 S11:095 S12:050 S18:000 S25:005 S26:001 S36:007 S37:000 S38:020 S44:003
S46:136 S48:007 S49:008 S50:255 

STORED PROFILE 0:
B1 E0 L0 M0 N1 P Q0 V1 W0 X4 Y0 &C1 &D3 &G0 &J0 &K3 &Q5 &R0 &S1 &T4 &X0 
S00:001 S02:043 S06:002 S07:050 S08:002 S09:005 S10:000 S11:095 S12:050 S18:000
S25:005 S26:001 S36:007 S37:000 S38:020 S44:003 S46:136 S48:007 S49:008 S50:255

STORED PROFILE 1:
B1 E0 L0 M0 N0 Q0 T V1 W0 X4 Y0 &C1 &D3 &G0 &J0 &K3 &Q6 &R0 &S1 &T4 &X0 
S00:000 S02:043 S06:002 S07:050 S08:002 S09:005 S10:000 S11:095 S12:050 S18:000
S25:005 S26:001 S36:003 S37:000 S38:020 S44:003 S46:136 S48:007 S49:008 S50:255

About 1: The only reference I can find to a setting that would include
error correction is AT&Qn although the manual is unclear: It says 
that n=9: Attempt V.42bis with fallBACK to V.42 (LAPM) ... I thought
that V.42bis was error COMPRESSION and V.42 (LAPM) was error CORRECTION.
How can the manual compare those two things? Or should I pick AT&Q5:
Select error correction mode. Which error correction are they talking and
are there other settings I need worrying about? In order to get rid of
the MNP stuff I set AT\N0, which in terms lead to &Q6 instead of &Q5.
This don't seem to make much sense since the manual says about &Q6 select
speed buffering.

About 2: The manual says: AT%Cn; where n=0 disables, and n=1 enables
data compression.  The exactly same thing does it say about %Mn.
Does one of them disable V.42bis and the other MNP-5 or how is this
to be understood?

(Bear in mind that the manual says that the 'AT%' commands are related to
V.42/V.42bis operation, and that they have another set of commands 'AT\'
who takes care of MNP settings)

About 3: The manual says AT%En selects auto retrain on/off. The manual
doesn't say anything about weather it will actually go back up to higher
speeds if the line becomes better again?

Also the manual says (p 72) ... ATN1 (default) allows communication at any
speeds supported by both modems ... ATN0 requires that the speed of the 
connection be ... specified by the value of S37 ... then (p 53) the 
manual contradicts itself by saying S37 ... This register is effective
only if an ATN1 command is issued... Now what do I beleive???

So if I understand the manual correct the settings I need are the 
following. Please feel free to comment with suggestions.

(for the 'standard setup')
AT &D3 &C1 &S1 &K3 E0 &Q5 
   |   |   |   |   |  |  
   |   |   |   |   |  +--> Select error correction mode
   |   |   |   |   +--> Disable echo of commands to screen
   |   |   |   +--> Enable RTS/CTS
   |   |   +--> DSR active according to CCITT specs
   |   +--> DCD
   +--> DTR 

(for the setup discussed above)
AT %C0 %M0 %E1
   |   |   |
   |   |   +--> Enable auto-retrain
   |   +--> Disable data compression (again, sigh)
   +--> Disable data compression 

Geesh, I wish those guys at Boca could learn to write a readable manual!

Disclaimer: I'm aware that my writing above may be difficult to understand.
It reflects the Boca manual!


-- 
Rene Madsen                
Unix Systems Support/Dev.       
madsere@okys.infoserv.com      
Newsgroups: comp.dcom.modems,biz.comp.telebit