User guide

User Guide

6. CDMA Modem Application

In most modem applications the SC105 can be used with the factory defaults.

This sets the SC105 up as modem enable 9600 baud, 8 data bits, Parity None

and 1 stop bit. It also sets the DTR dead time to 2 seconds. This dead time is

used to prevent characters produce by the modem from waking the datalogger up

right after communications has been terminated. The dead time can be adjusted

by changing the RS-232 DTR and RTS mode to Custom.

The CS I/O port configuration has several other modes that can be used

depending on the operating system used in the datalogger. These other modes

offer advantages for some applications. When using the PakBus OS, SDC7 or

SDC8 can be used. This allows communications from multiple sources at the

same time (for example, CDMA modem, RF400, and CR10KD).

Valid modes by Operating System:

Modem

Enable

SDC 7, SDC 8 SDC 9

Standard OS (Array) X X

Table Data OS X

PakBus OS X X

7. Freewave Radio Application

Typically, the Freewave Radios will be used in a PakBus network, with PakBus

OS dataloggers.

With a PakBus datalogger, the CS I/O port configuration on the SC105 should

be set to SDC 7 or SDC 8. The RS-232 baud rate should be set to match the

baud rate on the Freewave radios (38.4 k or 115 k are good choices).

If the low power modes of the Freewave radios are to be used, the SC105 DTR

and RTS mode setting will need to be configured to compensate for the turn-on

latency of the Freewave radio. The radio uses the RTS signal to go in and out of

its low power mode. The radio requires a delay from the time that it is brought

out of the low power mode and the time it receives data over the

RS-232 port.

To do this, the default DTR and RTS mode will have to be changed to Custom

with RTS High = 100, and RTS Low = 20. This gives 100 msec between RTS

HI and data on the RS-232 port, and 2 seconds between data on the RS-232 port

and RTS going LO.

For a detailed Application Note on using Freewave Radios, see PakBus

Networking with Freewave Radios. This application note gives complete details

on the set-up of the datalogger, the SC105, the Freewave radio, and LoggerNet

PC software for this application.