Communicating Thru COM /Serial port

Question

Hi,
I am developing POS system. The Display pole is connected on com1 and cash drawer on serial port. Can anyone help me how if i have a variable var_amt and want to display it on the pole[com1] what command to use i.e. how to open com / serial port thru forms.
Thanks in Advance

Answer 1

We have an old Forms application that needed to dial a modem through the serial port. Here's some code to maybe get you started. I'm going to assume you're on Windows.
Step 1:
Attach an OLE object to your canvas, and point that to MSCOMMLib.MSComm.1 (the MS serial port handler).
Step 2:
Sample code. This is our DIAL_PHONE proedure that receives a phone number, opens the COM port (in our case COM2), sends the modem dial strings, and waits for a respomse back from the mode. I'm not an expert, we just taught ourselves enough to get this one functionality to work.
/* Receives phone string, including area code, and dials a modem on COM2. Disconnects 9 seconds
after dialing (S7=09), assuming the telemarketer will have switched control to their headsets by then
PROCEDURE dial_phone(phone_number IN OUT VARCHAR2) IS
CommHandle     ole2.obj_type;     -- to hold the interface pointer
hold          number;
modem_init     VARCHAR2(30) := 'ATQ0V1E1S0=0X4S7=5';
dial_string     VARCHAR2(20);
com_err          VARCHAR2(100);
outBuf          NUMBER;
inchar          varchar2(100) := ' ';
loop_count     NUMBER(9) := 0;
dial_msg     varchar2(100);
time_start binary_integer;
time_end binary_integer;
z          NUMBER := 0;
delay      NUMBER := 100000;
--Return from check exchange
phone_to_dial     VARCHAR2(15);
X VARCHAR2(15);
BEGIN
IF     phone_number IS NULL
THEN     x := win_alert('OK','No phone number to dial.');
     raise form_trigger_failure;
END IF;
logit(:global.debug,'======== Begin DIAL_PHONE (' || phone_number || ') ==============');
-- Check exchange #, If it's in local calling area don't use an area code. Will also
-- add user's long distance data to the number returned, if necessary,
phone_to_dial := check_exchange(phone_number);
CommHandle := forms_ole.get_interface_pointer('b_main_prospect_info.mscomm_ocx');
--Set up the dial string with the passed phone number
dial_string := 'ATDT9' || phone_to_dial;
dial_msg := 'Dialing ' || dial_string || '...';
message(dial_msg,NO_ACKNOWLEDGE);
synchronize;
-- Set the com port to COM2.
OLE2.SET_PROPERTY(CommHandle, 'CommPort', 2);
-- try to close COM2, in case it was open for some reason. 0 = FALSE, -1 = TRUE
begin
OLE2.SET_PROPERTY(CommHandle, 'PortOpen', 0);
exception
when others then null;     -- if already open, ignore error
end;
-- Set modem to 1200 baud, no parity, 8 data, and 1 stop bit.
OLE2.SET_PROPERTY(CommHandle, 'Settings', '1200,N,8,1');
-- Open the port. 0 = FALSE, -1 = TRUE
OLE2.SET_PROPERTY(CommHandle, 'PortOpen', -1);
-- find out if the com port has opened successfully. 0 = FALSE, -1 = TRUE
hold := OLE2.GET_num_PROPERTY(CommHandle, 'PortOpen');
IF hold = 0 THEN --the com port could not be opened.
X := WIN_ALERT('OK', 'Your COM2 port (modem) could not be opened. Contact your supervisor');
RAISE form_trigger_failure;
END IF;
-- Send the attention command to the modem. Default setup string
OLE2.SET_PROPERTY(CommHandle, 'Output', modem_init || chr(13));
z := 0;
loop
z := z + 1;
exit when z = delay;
end loop;
-- Run program that give windows control to process info. in output buffer to modem
HOST(:global.gtec_dir || 'DEVENTS.EXE');
--Send the dial string
OLE2.SET_PROPERTY(CommHandle, 'Output', dial_string || chr(13));
z := 0;
loop
z := z + 1;
exit when z = delay;
end loop;
-- Run program that give windows control to process info. in output buffer to modem
HOST(:global.gtec_dir || 'DEVENTS.EXE');
--Clear the dialing string from the input buffer
OLE2.SET_PROPERTY(CommHandle, 'InBufferCount', '0');
* Loop until we get a BUSY or NO CARRIER signal.
loop_count := 0;
time_start := dbms_utility.get_time; -- store loop start in 1/100's of seconds
inchar := ' ';
     LOOP
     -- Run program that give windows control to process info. in output buffer to modem
     HOST(:global.gtec_dir || 'DEVENTS.EXE');          
outBuf := OLE2.GET_NUM_PROPERTY(CommHandle, 'InBufferCount');
     --Read the response data in the serial port, character by character.  Build INCHAR
inchar := inchar || OLE2.GET_CHAR_PROPERTY(CommHandle, 'Input');
     --message(inchar);
OLE2.SET_PROPERTY(CommHandle, 'InBufferCount', 0);
     * Check to see if a BUSY has been returned
IF INSTR(inchar, 'BUSY') <> 0 THEN
     --Close the port
     OLE2.SET_PROPERTY(CommHandle, 'PortOpen', 0);
     -- Release the MSCOMM handle
OLE2.release_obj(CommHandle);
     --Set the list to busy
     :b_main_prospect_info.CALL_STATUS_LIST := 'BUSY_NO_ANSWER';
     --Process a call marked as Busy/No Answer
     process_busy_no_answer;
EXIT;
     END IF;
IF INSTR(inchar, 'RING') <> 0 THEN
     message(inchar || ' ...', ACKNOWLEDGE);
     inchar := ' ';
     END IF;
     * Check to see if a NO CARRIER has been returned
     IF INSTR(inchar, 'NO CARRIER') <> 0 THEN -- happens when they switch to headset. No message shows.
     --message('NO DIAL TONE' || ' ...', ACKNOWLEDGE);
     inchar := ' ';
     GO_ITEM('CALL_STATUS_LIST');
EXIT;
     END IF;
     *Check to see if a OK has been returned
     IF INSTR(inchar, 'OK') <> 0 THEN
     message(inchar || ' ...', ACKNOWLEDGE);
     inchar := ' ';
     GO_ITEM('CALL_STATUS_LIST');
EXIT;
     END IF;
loop_count := loop_count + 1;
IF MOD(loop_count,1000) = 0
     THEN dial_msg := dial_msg || '.';
          message(dial_msg,NO_ACKNOWLEDGE);
          synchronize;
     END IF;
time_end := dbms_utility.get_time;
-- Compare current time to loop start time in 1/100's of seconds. If more than 10 seconds, end.
if time_end - time_start > 1500
THEN message('Problem dialing number. Result response not received from modem.', ACKNOWLEDGE);
message(' ');
     GO_ITEM('CALL_STATUS_LIST');
EXIT;
END IF;
     END LOOP;
OLE2.SET_PROPERTY(CommHandle, 'Output', 'ATH' || chr(13));
z := 0;
loop
z := z + 1;
exit when z = delay/10;
end loop;
--Close the port
OLE2.SET_PROPERTY(CommHandle, 'PortOpen', 0);
OLE2.release_obj(CommHandle);
--Give list box focus
update tele.gtec_login_tbl
set last_dialed = phone_number,
last_dialed_time = sysdate
where v_user_id = user;
forms_ddl('commit');
if to_number(:global.address_id) > 0
then GO_ITEM('b_main_prospect_info.call_status_list');
else GO_ITEM('b_manual_call.v_call_outcome');
end if;
EXCEPTION
when others then
logit(:global.debug,'Error dialing phone');
--Give list box focus
if to_number(:global.address_id) > 0
then GO_ITEM('b_main_prospect_info.call_status_list');
else GO_ITEM('b_manual_call.v_call_outcome');
end if;
END;