3.0 CONFIGURATION
The Model 1203 is equipped with four strapping options that allow
configuration to a wide range of applications. To gain access to the
internal straps, loosen the hex nuts on the DB-25 connectors and pry
open the case between the plastic shell ears. Figure 1 shows the
location of each strapping option.
3.1 DATA RATE
The data rate strap controls the rate at which data is transmitted.
Adjust the strap to select one of the following options: 7, 14, 28, 56,
112 and 224 Kbps, or external clocking. If “external clocking” is
selected, the Model 1203 will automatically match the clocking between
your two synchronous devices. The default setting is 56 Kbps.
3.2 CARRIER DETECT
The carrier detect straps allow you to determine whether the carrier
is “constantly on” or “controlled by RTS”. By adjusting the strap, you
may operate in switched carrier, multi-point and/or hardware
handshaking applications. Port 1 and port 2 may be configured
separately. The defaults setting is ON for both ports.
3.3 RTS/CTS DELAY
The RTS/CTS delay straps determine the amount of delay
between the time the Model 1203 “sees” RTS and when it sends CTS.
In order to emulate either dial-up or leased line modems, you can set
this strap at either no delay or 6.6mS. Port 1 and port 2 may be
configured separately. The default setting is 6.6mS for both ports.
3.4 GROUND
The ground strap setting connects the protective ground from port
1 or 2 to the Model 1203’s signal ground. The default setting is port 1.
3
4
Data Rate
Carrier Detect
Port 1
Port 2
224 kbps
112 kbps
56 kbps
28 kbps
14 kbps
7 kbps
External Clock
Port 1
Port 2
0 mSec
6.6 mSec
Constant
Port 1 Frame
Ground connects
to signal ground
Port 2 Frame
Ground connects
to signal ground
RTS/CTS Delay
Ground
Controlled
Data Rate
Carrier Detect
Port 1
Port 2
512 kbps
256 kbps
128 kbps
64 kbps
32 kbps
16 kbps
External Clock
Port 1
Port 2
0 mSec
6.6 mSec
Constant
Port 1 Frame
Ground connects
to signal ground
Port 2 Frame
Ground connects
to signal ground
RTS/CTS Delay
Ground
Controlled
Figure 1. Strap settings for the Model 1203