COMHP 7404/-D25
CyberResearch
®
Serial Communications
6
©Copyright 2010
CyberResearch, Inc.
Clock Modes
The
COMHP 7404
employs a unique clocking option that allows the end user to select from divide by 4, and divide by 1
clocking modes. These modes are selected at Header J1.
To select the Baud rates commonly associated with COM: ports (i.e. 2400, 4800, 9600, 19.2, … 115.2K bps) place the
jumper in the divide by 4 mode (silk-screen D4).
To select the Baud rates above 115.2K select the divide by 1 mode (silk-screen D1).
Baud Rates and Divisors for the ‘DIV1’ mode
The following table shows some common data rates and the rates you should choose to match them if using the adapter in the
‘DIV1’ mode.
For this Data Rate
Choose this Data Rate
1200 bps
300 bps
2400 bps
600 bps
4800 bps
1200 bps
9600 bps
2400 bps
19.2K bps
4800 bps
57.6 K bps
14.4K bps
115.2 K bps
28.8K bps
230.4K bps
57.6 K bps
460.8K bps
115.2 K bps
If your communications package allows the use of Baud rate divisors, choose the appropriate divisor from the following
table:
For this Data Rate
Choose this Divisor
1200 bps
384
2400 bps
192
4800 bps
96
9600 bps
48
19.2K bps
24
38.4K bps
12
57.6K bps
8
115.2K bps
4
230.4K bps
2
460.8K bps
1
