COM Port Baud Rate

Is posible setting up a com port to baud rate bigger than 19200?
I saw Basic TTYSET and TTYGET but i don't find an explanation of EXTA or EXTB.
Someone have any clue?
Thanks.

------------------------------
Sergio Perin
Engineer
Baseware Systems
------------------------------

Sergio,

The speeds should be driven from the file PTERM.BAUD:
SORT PTERM.FILE,BAUD F1 F2 06:16:52am 17 Mar 2021 PAGE 1
0......... F1............. F2...........

0 0 HANGUP
1 50
2 75
3 110
4 134
5 150
6 200
7 300
8 600
9 1200
10 1800
11 2400
12 4800
13 9600
14 19200 EXTA
15 38400 EXTB

16 records listed.
>

The  numbers relate to the local system C header files for TTY device speeds.  The specific file will vary depending upon the Operating System as will the exact format, but on Linux it is /usr/include/asm-generic/termbits.h and the codes are in octal (which I think is the same format as used on HP):

<snip>
/* c_cflag bit meaning */
#define CBAUD 0010017
#define B0 0000000 /* hang up */
#define B50 0000001
#define B75 0000002
#define B110 0000003
#define B134 0000004
#define B150 0000005
#define B200 0000006
#define B300 0000007
#define B600 0000010
#define B1200 0000011
#define B1800 0000012
#define B2400 0000013
#define B4800 0000014
#define B9600 0000015
#define B19200 0000016
#define B38400 0000017
#define EXTA B19200
#define EXTB B38400
</snip>

AIX uses hexadecimal in : /usr/include/termios.h

<snip>
#define B0 0x00000000
#define B50 0x00000001
#define B75 0x00000002
#define B110 0x00000003
#define B134 0x00000004
#define B150 0x00000005
#define B200 0x00000006
#define B300 0x00000007
#define B600 0x00000008
#define B1200 0x00000009
#define B1800 0x0000000a
#define B2400 0x0000000b
#define B4800 0x0000000c
#define B9600 0x0000000d
#define B19200 0x0000000e
#define B38400 0x0000000f
</snip>

As can be seen - different Operating Systems use slightly different files and file formats - hexadecimal vs. octal in these examples.

From the format it looks like EXTA and EXTB are synonyms for 19200 and 38400 respectively, and (from memory) the ceiling in the distant past was 9600, so 19200 and 38400 were I think added later. That would suggest that EXTA and EXTB mean no more than  'Extra A' and 'Extra B' as synonyms.

As the C header files stop at 38400 I suspect this is the limit - at least on Linux and AIX - for standard TTY devices and also seems to be a POSIX standard, though if other O/S versions have additional speeds then it may be a matter of just adding any extra codes to PTERM,BAUD so would be worth a try, Otherwise as a C header limit I suspect the ceiling for a standard  device would be 38400.

Hopefully this helps

------------------------------
John Jenkins
Principal Technical Support Engineer
Rocket Software Limited
U.K.
------------------------------

Sergio,

The speeds should be driven from the file PTERM.BAUD:
SORT PTERM.FILE,BAUD F1 F2 06:16:52am 17 Mar 2021 PAGE 1
0......... F1............. F2...........

0 0 HANGUP
1 50
2 75
3 110
4 134
5 150
6 200
7 300
8 600
9 1200
10 1800
11 2400
12 4800
13 9600
14 19200 EXTA
15 38400 EXTB

16 records listed.
>

The  numbers relate to the local system C header files for TTY device speeds.  The specific file will vary depending upon the Operating System as will the exact format, but on Linux it is /usr/include/asm-generic/termbits.h and the codes are in octal (which I think is the same format as used on HP):

<snip>
/* c_cflag bit meaning */
#define CBAUD 0010017
#define B0 0000000 /* hang up */
#define B50 0000001
#define B75 0000002
#define B110 0000003
#define B134 0000004
#define B150 0000005
#define B200 0000006
#define B300 0000007
#define B600 0000010
#define B1200 0000011
#define B1800 0000012
#define B2400 0000013
#define B4800 0000014
#define B9600 0000015
#define B19200 0000016
#define B38400 0000017
#define EXTA B19200
#define EXTB B38400
</snip>

AIX uses hexadecimal in : /usr/include/termios.h

<snip>
#define B0 0x00000000
#define B50 0x00000001
#define B75 0x00000002
#define B110 0x00000003
#define B134 0x00000004
#define B150 0x00000005
#define B200 0x00000006
#define B300 0x00000007
#define B600 0x00000008
#define B1200 0x00000009
#define B1800 0x0000000a
#define B2400 0x0000000b
#define B4800 0x0000000c
#define B9600 0x0000000d
#define B19200 0x0000000e
#define B38400 0x0000000f
</snip>

As can be seen - different Operating Systems use slightly different files and file formats - hexadecimal vs. octal in these examples.

From the format it looks like EXTA and EXTB are synonyms for 19200 and 38400 respectively, and (from memory) the ceiling in the distant past was 9600, so 19200 and 38400 were I think added later. That would suggest that EXTA and EXTB mean no more than  'Extra A' and 'Extra B' as synonyms.

As the C header files stop at 38400 I suspect this is the limit - at least on Linux and AIX - for standard TTY devices and also seems to be a POSIX standard, though if other O/S versions have additional speeds then it may be a matter of just adding any extra codes to PTERM,BAUD so would be worth a try, Otherwise as a C header limit I suspect the ceiling for a standard  device would be 38400.

Hopefully this helps

------------------------------
John Jenkins
Principal Technical Support Engineer
Rocket Software Limited
U.K.
------------------------------

Mr. Jenkins:
Thank you for answer my question.
I tried new items in PTERM.FILE,BAUD 16 and 17 for 57600 and 115200 baud.
The connections in both speeds worked flawlessly.

------------------------------
Sergio Perin
Engineer
Baseware Systems
------------------------------