
ZENO
®
-3200 USER MANUAL
Coastal Environmental Systems (206) 682-6048
Page 88
ZENO COM3 DE-9F MODEM DE-9F
shield
DCD 1 1 DCD
RXD 2 2 RXD
TXD 3 3 TXD
4 4
SG 5 5 SG
6 6
7 7 RTS
CTS 8 8 CTS
9 9
Figure 6-5. 9-pin to 9-pin, modem-to- ZENO
®
-3200 cable.
In the case of a low-power IDC modem, the ring detect line comes from the
ring-indicator (RI) line
108
on the modem and is wired separately to the
digital input specified in the ZENO
®
-3200 configuration.
6.5. CELLULAR MODEMS
Cellular modems are sophisticated radio modems. They require more steps
to integrate than a standard telephone modem, such as internal cellular
modem configuration and activation.
Configuration of the ZENO
®
-3200 itself for use with a cellular modem is
essentially the same as the telephone modem.
Since wireless communications is prone to noise, Coastal Environmental
Systems recommends that the bit rate (baud rate) be set to 4800 BPS
throughout the communications interface to provide the best bit rate ratio
and link reliability.
This means that the bit rate of the ZENO
®
-3200 COM port selected for the cellular modem
communication should be set to 4800 BPS.
109
Further, the cellular modem will need to be programmed to
108
The ring-indicator (RI) line from a modem is wired to pin 9 on a DE-9 connector or pin 22 on a DB-25
connector.
109
Refer to section 6.1 for setting the COM port baud rate.
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