I have installed ppp under Digital Unix 4.0d on a
Digital Personal Workstation 600au.I connect to the
600au over dial up phone lines from a PC
running Windows 95 dial up networking.. While I am
able to connect and use ppp there are two peculiarities.
1. During a successful ppp dial up telnet connection,
there is about a 1-2 second delay between typing in a
command at the terminal prompt and receiving a response.
The connections are made at
26,400 bps. The extent of the delay appears to be
related to the amount of output generated. However,
no such delay is observed on a uugetty
connection (i.e. with a VT100 emulation program
running on the pc) where the response is almost
instantaneous and appears to be independent of the amount
of output produced.
Also this does not appear to be a path problem since
the commands being used are accessed early in the path
statement. How can I remove this delay?
man stty has some discussion of cr0...cr3 carriage
return delays but no details are given.
2. If pppd is running on the workstation while there
is no active dial up session, a voice phone call
placed to the workstation ( an incorrectly dialed number)
causes the TR line to drop on the modem connected to the ppp
port. After this, the modem will not answer an incoming
call even though auto answer is still on.I have
tried this with two modems made by different manufacturers
and the result is the same. Furthermore, if uugetty is
running on this port, TR is not turned off. So it
would appear that the dropping of TR is due to pppd.
The problem was solved by ignoring the DTR
signal using the Hayes command, AT&D0. I have not seen any
discussion of this in the ppp literature.
Has this action been observed by others?
Here are some details of the ppp connection. pppd is
activated by using init q and the following line in
/etc/inittab:
ppp:23:respawn:/usr/sbin/pppd +pap crtscts
-detach /dev/tty00 9600 login passive
(Note that the above 2 lines are on one line in the
inittab file but are shown here on two lines.)
Curiously, the 9600 is needed to connect at 26400. Usage
of 19200 instead will not allow for a connection to pppd,
i.e. a login prompt is not issued.
The /etc/ppp/options file has:
asyncmap 200a0000
escape 7e,7f,fe,ff,93
mru 1000
ipcp-accept-remote
netmask 255.255.255.0
:ip address of client
crtscts
debug
kdebug 7
lock
modem
I am aware that the :ip address of client
(which in the real file
is replaced by the numerical ip address) and the
ipcp-accept-remote are contradictory but they remain
in the file.
A pap-secrets file is also used. However, this file does
not appear to cause any problems.
Many thanks for your help.
Steve Guberman
slg_at_sci.org
Received on Wed Nov 10 1999 - 07:04:11 NZDT