1532_configuring

Q: When trying to set up my modem, getty seems to make my send and receive lights flash, and there are strange login processes running in my process table.

A: The problems you are seeing are due to your modem's 'character echo' setting. The character echo setting (typically set with ATEx where x = 1 or 0) tells the modem to either echo characters back or not. Character echo should be turned OFF.

The following list contains suggestions that can help you configure your modem properly:

A hardware handshake cable should be used, and modem should be configured

properly for hardware handshaking (also known as rts/cts flow control).

For example: ATelebit T3000 uses register s68 to define hardware flow control. It

should be set for RTS/CTS flow control ON.

The entries in /etc/ttys and /etc/gettytab whether or not you are using the " f " flow control device drivers. For example:

ttyda "/usr/etc/getty std.9600" unknown off secure

^ is not using hardware flow control

ttydfa "/usr/etc/getty std.9600" unknown off secure

^ is using hardware flow control
Note: The "f " device drivers are cufa, cufb, ttyfa, ttyfb, ttydfa, and ttydfb.

The speed of your getty entry should match the speed your modem is set to. It is
important to lock the DTE rate, and set getty to the same speed. For example:

localhost# grep std.9600 /etc/gettytab

2|std.9600|9600-baud:\
:sp#9600:

localhost# cu -s 9600 -l /dev/cufa

Connected
at&v
T3000SA - Version LA3.00 - Active Configuration
B1 E0 L2 M1 Q0 T   V1 X1 Y0
&C0 &D0 &G0 &J0 &L0 &Q0 &R3 &S0 &T4 &X0
S000=0   S001=0   S002=43 S003=13 S004=10 S005=8   S006=2   S007=40
S008=2   S009=6   S010=14 S011=70 S012=50 S018=0   S025=5   S026=1
S038=0   S041=0   S045=0   S046=0   S047=4   S048=0   S050=6   S051=4
S056=17 S057=19 S058=3   S059=0   S060=0   S061=1   S062=15 S063=0
S064=0   S068=2 S069=0   S090=0   S093=8   S094=1   S100=0   S102=0
S104=0   S105=1   S111=255 S112=1   S180=2   S181=1   S183=25 S190=1
S253=10 S254=255 S255=255
OK

The S50 and S51 registers are set specifically for 9600 baud. Echo is OFF with ATE0.

In addition, if speeds of 38,400 baud are required, an entry like the following should be added to /etc/gettytab:

std.38400|38400-baud:\
:sp#38400:

QA900

Valid for 1.0, 2.0, 3.0, 3.1

	A hardware handshake cable should be used, and modem should be configured
	properly for hardware handshaking (also known as rts/cts flow control).

	For example: ATelebit T3000 uses register s68 to define hardware flow control. It
	should be set for RTS/CTS flow control ON.