Testing your Bell 202 Modem

Your Bell 202 modem comes fully tested from the factory. However if you need to perform some tests on an installed modem, we have put together a few scenarios which may help to determine if the modem is operating correctly.

Loopback Switch (SW2)

The loopback switch allows you to disconnect the analog output signals from the telephone line, and loopback the transmit and receive signal though a 10 dB pad. The 10 dB pad simulates a telephone line, and ensures the transmit signal does not override the receive signal. You can then transmit RS232 data on the transmit pin of the DB25 connector (pin-2), and the same RS232 data is received on pin-3 of the DB25 The loopback switch is located on the front panel of the Bell 202 modem enclosure.

The following steps describe the test procedure for the single-channel modem:

• Connect the Bell 202 modem to a PC or laptop COM Port using a straight-through modem cable.
• Run a terminal program such as Hyper terminal on Windows.
• Set the terminal program to the appropriate communication port (for example, COM 1). Set the baud rate to 1200 bps, and set the Flow control to Hardware.

• Place the Bell 202 modem in Loopback, by pushing in the Loopback switch.
• Type a letter on the keyboard. You should see the letter displayed on the terminal screen. The ASE modem LED's (TX, RX, RTS, CTS, and CD) should flash when the keystroke is entered. The Power LED should always remain on.

This simple test verifies both the sending ad receiving portion of the Bell 202 modem.

You may contact us in Campbell, CA by phone at 408-364-0500, fax to 408-364-0550, or via email at products@ase-systems.com.

Normal business hours are 9:00AM to 6:00PM Pacific Time, M - F.

Applied Systems Engineering, Inc.
1671 Dell Avenue, Suite 200
Campbell, California 95008
Phone: (408) 364-0500 • Fax: (408) 364-0550
Email: products@ase-systems.com

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