telnetlib problems

[vercingetorix52 at yahoo.com]

I'm trying to use a python script to access an embedded computer
running linux and connected via a crossover ethernet cable using the
following script...

...and I realize the username and password is not realistic... I'm
still in "proof of concept" stage here :)

#########################
import telnetlib

tn = telnetlib.Telnet('192.168.100.11')

tn.read_until('login: ', 5)

tn.write('user\n')

tn.read_until('Password: ', 5)

tn.write('password\n')

tn.read_until('bash-2.05$ ', 5)

tn.write('ls\n')

print tn.read_very_eager()
#########################

As a script, this doesn't work.  However, if I execute the same
commands interactively, it works fine.  If I insert some time delays as
follows...

#########################
import telnetlib
import time

tn = telnetlib.Telnet('192.168.100.11')

tn.read_until('login: ', 5)
time.sleep(2)
tn.write('user\n')

tn.read_until('Password: ', 5)
time.sleep(2)
tn.write('password\n')

tn.read_until('bash-2.05$ ', 5)

tn.write('ls\n')
time.sleep(2)
print tn.read_very_eager()
#########################

...and it works fine.  Can anyone tell me what's going on here? TIA