How the M90 works with a modem

To allow the M90 to use a modem, you simply select Use Modem in the M90 OPLC Modem Configuration box.

The charts below show the actual process--exactly how the M90 initializes and works with a modem. This information is provided for advanced users who may require it for a specific application, or for advanced troubleshooting.

Initialization

M90 Dialing

Note that in order to receive new calls, the application must end the call (hang-up) in order to free the communication port.

M90 Hang-up

When a call is not ended by the M90, SB 75 turns off and Error Code 1, No Carrier, comes into effect. This describes any situation where the connection is lost, as for example due to a loose cable.

Relevant System Bits, System Integers, and Modem Error Messages are listed below.

System Bits
SB	Symbol	Description
72	Initialize Modem	Causes modem initialization. Remains ON until initialization is complete, then turns off. Note that: This SB turns ON at power-up. You can disable this SB at power-up to avoid initializing the modem. You may use this SB to initialize the modem at any point during your application.
73	Modem Initialization: Succeeded	Signals that modem has been initialized. When SB 73 is ON, M90 is ready to both make and receive calls.
74	Modem Initialization: Failed	Signals that modem initialization failed. SI 70 contains the error code.
75	Modems Connected	Turns ON when connection is established
76	Disconnect Modem	Ends call (hang-up)
77	Dial Remote Modem	Dials the phone number represented by the index number stored in SI 71

System Integers
SI	Symbol	Description
70	Modem: Error Code	Contains an error code resulting from a modem error. The list is shown below.
71	Modem: Phone Number	Contains the phone number to be dialed. You create a phone book when you configure the modem. Each phone number in the phone book is linked to an index number. Use the Store Direct function to place the index number of desired phone number in SI 71, then activate SB 77 to dial it.

Error Messages ( SI 70)
Number	Error Message	Description
0	No Error	No error.
1	No Carrier	No carrier signal found--reason unknown. Check your communication cables.
2	Modem Did Not Reply	The modem referred to is the one on the M90 side.
3	No Dial Tone	No dial tone.
4	Line is Busy	The number dialed is engaged.
5	No Carrier While Dialing	Carrier signal was lost during dialing.
6	Modem Report Error	May be due to an incorrect number or unknown initialization commands.
7	Modem Report Unknown Message	An unrecognized message.
8	No Phone Number	SI 71 contains a number that is not linked to any phone number stored in the phone book.
9	RS232 Port Busy	The RS232 port is already in use.