rehat linux9.0 ppp error messages

hi, all
these days, I tried to test ppp link between two redhat
linux9.0(using null modem connection), acoording Chapter 29. Using PPP
across a null modem (direct serial) connection in PPP-HWOTO,,
but when I type
[root@localhost ~]# pppd /dev/ttyS0 nodetach
I got the following messages:

using channel 3
Using interface ppp0
Connect: ppp0 <--> /dev/ttyS0
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0x50ae4299>
<pcomp> <a ccomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0x50ae4299>
<pcomp> <a ccomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0x50ae4299>
<pcomp> <a ccomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0x50ae4299>
<pcomp> <a ccomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0x50ae4299>
<pcomp> <a ccomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0x50ae4299>
<pcomp> <a ccomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0x50ae4299>
<pcomp> <a ccomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0x50ae4299>
<pcomp> <a ccomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0x50ae4299>
<pcomp> <a ccomp>]
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <auth pap> <magic 0x50ae4299>
<pcomp> <a ccomp>]
LCP: timeout sending Config-Requests

I have done the following things:
1. the client(using minicom) can login into the server(using
agetty),
2.the configurations about server ppp as follows:
/etc/ppp/options:
lock
auth

/etc/ppp/options.ttyS0
lock
local
crtscts
debug
asyncmap 0
passive
proxyarp
192.168.1.1:192.168.1.10
netmask 255.255.255.0
ms-dns 192.168.1.1
require-pap
38400

/etc/ppp/pap-secrets
ppp * 123pcz *

3. the configuration about client ppp as follow
/etc/ppp/options:
lock

/etc/ppp/options.ttyS0
38400
crtscts
debug
local
user ppp
noauth

/etc/ppp/pap-secrets
ppp * 123pcz *

any replys are welcom, thks!

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