User guide

User Guide
5
'PC/PDA mode': DTR and RTS are both driven to 5 V.
'Modem mode': DTR will be driven to +5 V when the CS I/O interface is
active for Modem Enable, SDC Address 9, and
Addressed Print Device configurations. When the
CS I/O is inactive, DTR will be 0 V.
Additionally, there will be a 'dead time' after DTR is
dropped of 2 sec when data coming in on the RS-232 will
be ignored.
For SDC Address 7 or 8, DTR will always be driven to
+5 V.
RTS will 'key' the data; it will be driven (+5 V) 20 msec
prior to data being sent out the RS-232, and remain
driven for 5 seconds after the last data is sent out the RS-
232.
'Custom mode': This mode is identical to the 'Modem mode', except the
delays between RTS HI and data, data and RTS LO, and
the 'dead time' are all configurable.
4. Installation
Connect the SC105 to the RS-232 device and to the datalogger with the SC12 9-
pin cable (included). If the device has a 25-pin connector, a 9-pin female to 25-
pin male adapter is required (CSI PN #15751).
Proper transient protection should be installed to protect the computer and
datalogger in areas where damage due to lightning is possible. If this is a RAD
modem application, see Section 5.2.
5. RAD Modem Application
The SC105 is frequently used with a short-range modem to communicate across
a 4-wire, unconditioned dedicated line. Campbell Scientific offers a kit
(PN TBD) that includes the SC105, the 9- to 25-pin adapter (PN #15751), and a
mounting bracket (PN #6282). The bracket will mount the RAD, SC105, and
adapter to the back plate in a Campbell Scientific enclosure. This section
describes using a short-range asynchronous modem built by RAD*.
* SRM - 5A RAD Modem
RAD Data Communications, Inc.
900 Corporate Drive
Mahwah, NJ 07430
Tel: [phone]
Fax: [phone]
Email: [e-mail]
http://www.rad.com