gaps in graph using bash script

[orennu]

hi ,

i am using cacti with below info on ubuntu server 2.6.38-8-server #42-Ubuntu SMP Mon Apr 11 03:49:04 UTC 2011 x86_64

Date Wed, 26 Jun 2013 17:38:36 +0000
Cacti Version 0.8.7g
Cacti OS unix
SNMP Version NET-SNMP version: 5.4.3
RRDTool Version RRDTool 1.4.x
Hosts 18
Graphs 69
Data Sources Script/Command: 69
SNMP Query: 2
Total: 71

i am using bash scripts to sample my traffic and i noticed that there are gaps whenever value received from script is more than 999
when i run the script from cli i get the correct value but on graph i see -nan and gap.
i ran root@voip-server:~# rrdtool info /var/lib/cacti/rra/sbc1_in_calls_164.rrd
filename = "/var/lib/cacti/rra/sbc1_in_calls_164.rrd"
rrd_version = "0003"
step = 300
last_update = 1372267501
header_size = 3496
ds[in_calls].index = 0
ds[in_calls].type = "GAUGE"
ds[in_calls].minimal_heartbeat = 600
ds[in_calls].min = 0.0000000000e+00
ds[in_calls].max = 1.0000000000e+03
ds[in_calls].last_ds = "0"
ds[in_calls].value = 0.0000000000e+00
ds[in_calls].unknown_sec = 0
ds[out_calls].index = 1
ds[out_calls].type = "GAUGE"
ds[out_calls].minimal_heartbeat = 600
ds[out_calls].min = 0.0000000000e+00
ds[out_calls].max = 1.0000000000e+03
ds[out_calls].last_ds = "765"
ds[out_calls].value = 7.6500000000e+02
ds[out_calls].unknown_sec = 0

i think ds[out_calls].max = 1.0000000000e+03 is what causing this but i went through all console options on web and could not find this limit.
does anyone know how to modify this value ?