The following document provides an overview of how to set up an Asynchronous Modem. This is applicable to operating system level 3.2.5 or higher.
The following actions are required:
Attach a direct (modem) cable between the modem and any open serial port on the system.
NOTE: Although a modem can be attached to a 16 port adapter it is not recommended. The 16 port adapter had RTS looped back to CTS at the connector (physical RTS and CTS lines do not run between the system and the modem as they do in the other options). This renders RTS (hardware) flow control impossible resulting in possible data loss, communication errors, or no connection ability at all.
All options require a direct cable but each adapter has different pin-outs and requires a different connector on that direct cable (most modems are db-25 connected but there are some variations on the market).
NOTE: See Appendix C, "Modem cable pin outs" for various adapter attachments.
NOTE: See Appendix A, "Add/Change/Show a tty", for help with this function.
Special notes:
This file has many commented out lines. Append a new line to the bottom of the file.
NOTE: There cannot be any spaces or characters before the word "Direct". Do not hit "enter", add lines or spaces after "baud direct" when typing the command in the following step.
Direct ttyx - baud direct
(Where x is put the tty number assigned to the port by SMIT and replace "baud" with the speed or the tty you noted when SMIT created the tty. Such as Direct tty1 - 9600 direct)
Programming a modems register makes it respond accordingly to various conditions.
Most modern modems are Hayes compatible, so they will accept at commands to program their registers.
To program a modem, type the following on the command line:
cu -ml ttyx (x is the number of the modem tty)
(Response should be "CONNECTED")
at (Response read "OK")
at&f (Response should read "OK")
at&cl (Response should read "OK")
at&d2 (Response should read "OK")
ats0=1 (Response should read "OK")
atq2 (Response should read "OK")
at&w (Response should read "OK")
~[tilde].[period[
(represents <tilde><period>)
After hitting enter on the last command, the system will close the connection to the modem and give you a command line prompt. You are ready to test.
NOTE: See Appendix D, "Modem strings" for some modem specific strings.
cu -ml ttyx (x is your tty number)
(Response should read "CONNECTED")
at (Response should read "OK")
atdt0000000000
In about 30 sec to 1 min something like the following will appear on your screen:
CONNECTED AT 9600
This will scroll up and you will see the login prompt from the called system on your screen. Login in as normal and carry out whatever operation you need to do.
penable ttyx (x is your tty number)
This will start a getty (login prompt) running on the modem tty. Now call the phone number of the line attached to the modem on the system and you will get the login herald on your calling computer's screen.
The following chart lists the possible setting and their meaning.
The following is a list of responses the system may give other than Connected when you enter cu -ml tty1 on the command line.
NOTE: We will use tty1 and a baud of 9600 for our examples in this text. Type the following from the command line:
cu -ml tty1
(Response should read "CONNECTED")
The message Connection Closed -m flag not valid may occur on OS levels below 3.2.5. The -m flag tells the system to ignore missing CD and open the port. Lower OS levels do not have the -m flag option so we will need to use the Dialers file to send the modem the set up string of at commands.
Go to the bottom of the file and enter this line on a new line by itself:
set^^=,-,^^^"" at&c1&d2q1s0=1&w ""
(the "^" represent spaces)
Save the file.
Rather than a Direct line entry for the tty, enter the following on its own line:
ACU tty1 - 9600 set
Comment out all other tty entries by putting a pound sign at the front of each line.
cu -d 123
This will produce on-line debugging and you can see the steps of the cu command on the screen. The command will find the line ACU tty1 - 9600 set in the Devices file. Then it will go to the Dialers file and find the set chat script we entered. You will see on the screen a series of expect, gotit, send them lines. It then sends the at string to the modem and then hangs because the script was not programmed to dial the bogus phone number 123.
~[tilde].[period]
The modem has now been programmed. Edit /etc/uucp/Devices file and restore to
original condition.
The cu command response should be No Devices Available. This means the /etc/uucp/Devices file either does not contain the line, Direct tty1 - 9600 direct or the line is there, but it has a typo in it. The line must be exactly as follows:
Direct tty1 - 9600 direct
^ ^ ^ ^
(the "^" represent spaces)
If the line appears correct, there may be some non-printable typos in it. Delete the line and then add it again as previously outlined by typing:
The response will be Cannot Access Device or Device Locked. This means some other process has control of the tty. To find out what the process is, type from the command line:
ps -ef | grep tty1
If the process is a getty, run pdisable tty1.
If it is some other process, run kill -9 <process id>.
NOTE: Some processes must not be stopped with the -9 option (i.e. slattach), take the appropriate steps to kill the process and free the port.
In the case of slattach for example you would first run:
ifconfig sl(x) detach
kill # (# is process id of slattach)
If no process is returned except the grep itself, the port is hung and must be cleared.
To clear a hung port, see Appendix B, "Clearing a hung tty port".
The response from the system should be cu not found This indicates a missing uucp file set.
Run the following command:
lslpp -h *uucp*
If the system responds and the uucp fileset is not found on the system. Install the file set.
For a 3.2 system install 'bosext1.uucp.obj'.
For a 4.1 system install 'bos.net.uucp'.
After the installation of the fileset, return to normal mode to set up procedure.
This indicates the modem attached to the system has result codes turned on and is sending RING to the system when someone dials in.
To fix the above:
cu to the modem and send command atq2. If modem will not accept q2 send atq1. (After sending atq1 the modem will not respond with "OK" because you have turned all result codes off. The code atq0 will turn them back on). If the modem accepts atq2 but still asks for RINGs then send the password atq1.
ps -ef | grep ttyx
If a getty is not running, type the following command:
penable ttyx
then dial in again.
If you penable the getty and it dies or you see a console message of Init Respawning Too Rapidly, the carrier detect (CD) is high on the port. To verify this run the following command:
/usr/lbin/tty/stty-cxma ttyx | pg
The output is a snapshot of the line conditions of the tty, (+) is high and (-) is a low. If you see CD+ and no one is dialed into the modem, this indicates a problem. Carrier detect should only go high when another modem calls the system. Either the modem is sending the CD or the system is altering the port itself. The quickest way to check where the problem lies is to turn the modem off, and run the following command again:
/usr/lbin/tty/stty-cxma ttyx | pg
If you see CD- the modem is the problem. It must either be reprogrammed or it is not functioning properly and should be replaced. Try at&c1 or check the modem's manual for the proper command to have CD follow the line signal.
If however, you still see CD+ with the modem off, the system is the cause. Check the following:
NOTE: If you are using a 8 wire cable off a 128port adapter RAN unit there is an error in the original cable diagram, see Appendix C, "Modem cable pin outs" for correct pin to pin connections.
stty -a < /dev/ttyx | pg
Look for the output clocal (not -clocal). If you see it listed go into SMIT and do a change/show on the tty. On the final screen you will see two lines called STTY runtime attributes and STTY login attributes. On both of the lines scan the list of attributes in the [] box to the left. Find and delete the clocal attribute found in either of the lines. Run the following command to make the change take effect:
rmdev -l tty
NOTE: If the system says the device is busy, run the following command:
pdisable ttyx
then repeat the following command:
rmdev -l tty
Type mkdev -l ttyx If you do not find clocal listed, check the tty settings in SMIT for either Force Carrier or Ignore Carrier being Enabled.
Getty is only run on a SHARE/DELAY tty when someone dials into the modem (and CD goes HIGH) The problem is the same as in step 2 above. The port is seeing CD high when no one is dialed in. Troubleshoot the same way as step 2.
NOTE: When the getty is running, it should not be associated with the tty until another modem dials in and CD goes high.
To set the 'baud' as stated in the modems manual or on the system, from the command line run:
cu -s(baud) -ml ttyx
For example if you run cu -s19200 -ml tty1 this will open the tty1 port at a speed of 19200.
When you see Connected type on the command line:
at
The response from the modem should read "OK".
You have now communicated with the modem at the 19200 baud speed and the modem now matches the port speed.
NOTE: Most modems run with v.32 compression. This can give up to a 4 to 1 compression. A 14,400 bits/secmodem compressing 4 bits to 1 bit results in 14,400 times 4 which is 57600 bits/sec. You can set a tty to run at 38400 and program the modem for the same speed because it could run faster than 38,400 bits/sec.
The most common dial out problem is getting connected and then getting garbage characters or nothing after the connect to the other modem.
The number one cause of this problem is a 'baud' rate mismatch between the modem and the tty it is attached to.
Three baud rates must match.
Look at the 'tty baud via smit', then run the following command:
cu -s(baud) -ml ttyx (i.e. cu -s9600 -ml tty1)
This will open the port at the baud rate of the -s flag on the command line. You should see the response Connected.
From the command line type:
at (You should get the response "OK")
You have now set the modem to the -s flag speed.
If you get an error on this command run, cu -ml tty1. When you get Connected, set the baud rate with the proper at command for your particular modem.
NOTE: If you cu to modem and get Connected but the cursor does not respond to key strokes or you do not get an "OK" then enter the following: (You will not be able to see what you typed):
ate1 "enter" atq0 "enter";
These two commands should turn the echo and answer codes back on in the modem.
If you still do not get screen activity, it could be due to one of the following reasons:
For example if you can see the TD light on the modem flicker when you are typing but you cannot see anything on your screen; this would indicate a bad modem or cable in the RD line because you can talk to the modem but it cannot send a signal back to the system.
You may also have bad hardware in the setup (modem, cable, etc.). Check your hardware, especially a new setup that has never worked prior to this attempt.
To add a tty to the system, log on or su to root. Then type SMIT or smitty on the command line. Select the following order of options:
DEVICES
TTY
ADD A TTY
RS232
(SELECT PARENT ADAPTER)
(SELECT PORT NUMBER)
Remember to see the section on "Create a tty on the chosen port" for special settings that need to be made on the same screen where you enter the port number.
To "change/show" a tty you must be root user, then start SMIT and select the following options:
DEVICES
TTY
CHANGE/SHOW CHARACTERISTICS OF A TTY
(SELECT THE DESIRED TTY)
(CHANGE OR VERIFY THE ATTRIBUTES)
NOTE: On some 3.2 systems after you have selected the tty you wish to work with, there is a sub window giving you 4 options for different groups of attributes. The most commonly chosen are tty program and tty hardware characteristics. Select one of the four attributes for the final change/show to work with. If it is not in the group you chose, select one of the others.
There are numerous reasons that cause a port to hang or to try and free them up again.
fuser -k /dev/ttyx
This sends a hangup signal to all processes registered on the port. Or try:
/usr/lbin/tty/stty-cxma flush ttyx
echo tty ttyx | crash | more
This will give a screen output. Take note of two pieces of information:
This means the port is stuck open but there is no process to kill.
fuser -k /dev/ttyx
NOTE: The following command is done as a last resort before rebooting the system because if something is hung this also may hang while trying to work with the odm. If that happens it will require a reboot.
/usr/lbin/tty/stty-cxma flush ttyx
If none of these attempts result in freeing the tty, so a cu can be run, the only option is to re-boot the system. (This is especially true in the case of /usr/lbin/tty/stty-cxma flush ttyx, having no pid number but a reading of open on the port.)
rmdev -l ttyx and #mkdev -l ttyx
This step will remove and re-add the tty which may clear the port.
Cable-B Adapter-to-DB25 S1/S2 Serial Port
PN00G0943 FFC 252
10 9 8 7 6 SIGNAL SYSTEM DEVICE
------------------ NAME END END
|_ * * * * * _|
| * * * * * | TXD 1 2
-------------- DTR 2 20
5 4 3 2 1 RTS 3 4
10-pin rectangular RI 4 22
(system end) FEMALE NOT USED - -
RXD 6 3
DSR 7 6
CTS 8 5
1 13 DCD 9 8 DSR 7 6
__________________________ SIG GND 10 7 DB-25 MALE CONNECTOR
\. . . . . . . . . . . . . / (device end)
\. . . . . . . . . . . . /
------------------------
14 25
DB-25 MALE CONNECTOR
(device end)
DIRECT CABLE FOR HOOKING MODEM TO NATIVE SERIAL PORT ON SOME 6000s
CABLE-D ASYNC EIA-232 MODEM CABLE
PN6323741 10FT FFC 259
13 1 System Device
Signal End End
___________________________
\ O O O O O O O O O O O O O / Shield Gnd Shell Shell,1
\ O O O O O O O O O O O O / TD 2---------2
------------------------- RD 3---------3
25 14 RTS 4---------4
DB-25 FEMALE CONNECTOR CTS 5---------5
(system end) DSR 6---------6
Sgnl Grnd 7---------7
1 13 CD 8---------8
___________________________ DTR 20---------20
\ . . . . . . . . . . . . . / RI 22---------22
\ . . . . . . . . . . . . /
-------------------------
14 25
DB-25 MALE CONNECTOR
(device end)
STRAIGHT THROUGH DIRECT (MODEM) CABLE
CABLE - P RJ-45 TO DB25 CONVERTED CABLE
PN59F3432 FFC266
64port CONCENTRATOR
RJ-45 CONNECTOR
_________
| |
______________|_______|___________ Signal
| | Name Concentr Device
| |
| {} {} {} {} {} {} {} {} | Shld Gnd 1 1
---------------------------------- RTS 2 4
1 2 3 4 5 6 7 8 RD 3 3
CD 4 8
Sgnl Gnd 5 7
1 13 TD 6 2
___________________________ DTR 7 20
\ . . . . . . . . . . . . . / CTS 8 5
\ . . . . . . . . . . . . /
-------------------------
14 25
DB-25 MALE CONNECTOR
(device end)
STRAIGHT THROUGH DIRECT (MODEM) CABLE
(64port adapter to modem off concentrator)
CABLE NK 10-PIN TO DB25 DIRECT RAN CABLE PN43G0935
Remote Async Node End
RJ45 10-pin
Signal Remote
Name Async Device
_________ RJ45 DB25
| |
__________________|_______|________________ RI 1 22
| | DSR 2 6
| | RTS 3 4
| {} {} {} {} {} {} {} {} {} {} | Chassis Gnd 4 Shell
------------------------------------------ TD 5 2
1 2 3 4 5 6 7 8 9 10 RD 6 3
Signal gnd 7 7
CTS 8 5
DTR 9 20
1 13 CD 10 8
___________________________
\ . . . . . . . . . . . . . /
\ . . . . . . . . . . . . /
-------------------------
14 25
DB-25 MALE CONNECTOR
(device end)
This cable is not interchangeable with the 64-port RJ45 to DB25 Cable-P
10 PIN RAN DIRECT (MODEM) CABLE
The following are modem strings that work for certain modems.
NOTE: In all cases following, if the modem gives an error on the whole string, enter each register separately as shown in "Program the modem" section.
===========================================================
HAYES ACCURA
AT&F&C1&D2S0=1Q2&W
===========================================================
MULTITECH MULTIMODEM II
Use ATL5 ATL6 and ATL7 to view the settings:
Change each register individually i.e.
AT$MB9600 or ATB1 or AT$SB9600
Set the registers as follows:
ATL5
B1 E1 M1 Q0 R0 V1 X0 &E1 &E4 &E6 &E8 &E10 &E13 &E15
$MB9600 $SB9600 $BA0 &W0
ATL6
S0 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S13
001 043 013 010 088 002 045 002 017 007 070 037
S24 S25 S30
020 001 000
ATL7
$A0 &A0 #A0 &B0 &BS1 &C1 $D0 &D2 #DB0 $EB0 %E1 #F0 $F1
&G0 #L0 $MI0 &M0 &P0 #P2 &Q0 $R0 &R1 &RF1 &S0 $SP0 &SF0
#T1 $V0 $V6 $VD0 &X0 Y0 $MB9600 $SB9600 $BA0 &W0
NOTE: ONE IMPORTANT ITEM ON THIS MODEM IS TO MAKE SURE
THE $MB AND $SM REGISTERS ARE THE SAME BAUD RATE AND
THAT BAUD IS THE SAME RATE THAT THE TTY IS SET TO
===========================================================
PRACTICAL PERIPHERALS
AT&FM1&D3&C1L0E0Q2S0=1&WX4
===========================================================
TELEBIT T1600
ATS0=1S2=255S7=60S11=50S41=2S45=255S51=252S63=1S58=2S64=1 ATS69=2S105=0S111=30S255=0M0&C1Q2&D3&Q0&R3&S1&T5 ========================================================== UDS MODEM AT&FQ2E0Y0&C1&D2&S1%B5%E0*LC&W =========================================================== U.S. ROBOTICS 28.8 or 33.6 SPORTSTER AT&F&B1&B1&C1&D2&H1&I0&R2&K3&N0Q2S0=1&W
NOTE: In both cases be sure to set the no. 3 and no. 8 dip switches down and the rest up.
The second string sets the modem to use Xon (software flow control). Use AT&F1 rather than AT&F2 to set to RTS (hardware flow control)
All the above cases were done on individual modems and IBM systems. None are guaranteed to work in any particular case. They are only guide lines to be used. Consult your modem manual for additional information or call the modem manufacture, for additional set up and support.
[ Doc Ref: 90605210414772 Publish Date: Oct. 18, 2000 4FAX Ref: 6553 ]