SI-3
™
U
ser
’s M
anual
14
Typical ranges for an on-coming mid-sized sedan are:
Setting
Range (feet)
1
350
2
575
3
800
4
950
5
1300
6
1700
7
1875
8
2400
9
2800
10
>3000
The distances will vary based on location, body of the car and
alignment of the antenna . It is normal for the range to vary by 10%
on identical cars .
4.13 Serial Protocol
Refer to the product manual for more information on which protocol
to use . <D> is a direction character that is “+” for vehicles coming
towards the sign, “-“ for vehicles moving away, and “?” when the
direction cannot be determined . [S] represents the displayed speed .
If a period is within the square brackets it is the decimal point . Any
zeros are sent as described and do not change with a vehicle’s speed .
The <cr> signifies the end of the outgoing message . The default
setting is <D>[SSS .]<cr> . Other protocols listed are used by Decatur
for testing purposes . Zero Suppress
When this value is selected the SI-3™ will not send any information
over the RS232 port unless a vehicle is detected .
