Replace Computer with a Thumb Wheel Switch

....... to tune ABR 202 (C Band) Receiver 

 Simplicity is the need of the hour. As Engineers, we aim in simplifying things around us, so that it provides us a better, faster and easy way to terminate a task at hand. We take this opportunity to share with you on our project, on how to use a Decade switch to work hand in hand with a Radyne Comstream Digital Audio Receiver ABR202. This may eliminate need of computer for dialing tuning. 

For this project the basic Hardware and Software supports are:- (a)A Decade switch (thumb wheel) taken out from an old Synthesizer (b)Two nos. of D Connector(9pins male & female) (c)25 pins D Connector(female) (d) ABR202WINDRV software and (e)CAT 5/6 cables.

The main system connections are:-

(a)   From COM port (male) of personal computer to the M&C port(female) of Radyne Comstream Digital Receiver. For this, a parallel connection is made for the first five pins (ie.1 to 5).

(b)   From the Decade switch to the 25 pins Relay Port of the Radyne Comstream Digital Receiver. For this, connections are as follows.    

Decade switch point connector	25 pins Relays port
1	9th pin
2	10th pin
4	11th pin
Ground©	25th pin

System settings: For port settings

Open WINDRV

                                    From taskbar click TERMINAL

                                                                                           Click PORT SETTINGS

A Dialog box will appear, then select

·        NAME

·        COMPORT – Com1

·        BAUDRATE – 2400

·        DATABITS – 7 bits

·        PARITY – odd

·        STOP BITS – 1 bit

·        TERM/PACKET MODE – ASCII

             

A Com1 terminal dialog box will open. In this very window type your password if any and then, For Carrier configuration type

CC  ,,256000,1,3,0

For format definition type

FD  ,1,,7,0,0

For confirmation of settings type CC then Enter and then FD and then enter. Settings done will be displayed. Configurations for other desired frequencies can be done in the same way.

Now for Presettingthe decade switch to be operational we need to define channel frequencies from 0(zero) to 7(ie, 8 channels in the Com1 terminal dialog box) which we can configure according to our needs. We may note here that a channel 0(zero) of the decade switch will correspond to a channel frequency setting no.7 of the receiver and so on thus, giving a reverse operation.

After configuring all the settings, the receiver is made to be operational with the switch alone by giving the command ‘LC 1’ in the Com1 terminal dialog box. After doing so we may terminate COM port to M&C port because at this point the switch will be fully functionalized. If one desires to have PC based control then type the command ‘LC 0’ in the Com1 terminal dialog box.

Work done at AIR Shillong by Baki Syiem, EA & P.C. Lyngdoh, Technician under the guidance of Shri O.N. Pradhan, AE.

For details contact at "o n Pradhan" pradhanshg@gmail.com“Baki Siyem" kiiari.00@gmail.com