Testing the Business Modem using S-Resister 16 14-9Testing the BusinessModem usingS-Resister 16Register S16 is a bit-mapped register (See Appendix A, S-Registers, forinstructions for setting bit-mapped registers).Earlier modems require bit 3 to be enabled to grant digital loopbacktesting to a remote device. The Business Modem requires the &T4 settinginstead. To perform remote digital loopback testing with a modem thatdoes not use the &T test command, that modem should be set to S16=8.Analog Loopback (AL)S16=1DTo use the modem's Test Pattern (S16, bit 2) instead of typing your owndata, see RDL Testing Using a Built-in Test Pattern (S16=4).1 Send AT&M0&N3S14.0=0 to the modem to prepare for testing.This command disables error control, fixes the connection rate at 2400bps, and makes the Business Modem return to command mode whenyou type +++.2 Send ATS16=1D. The modem enters AL mode and sends a CONNECTresult code. The MR status light flashes.3 Type data to the modem for it to transmit, loop to its receiver, and outputto the screen.An alternative is to use the Test Pattern, described later.4 Send the escape code, +++, and then ATH to end the test.5 Send AT&M4, unless you used a reset command (ATZ or ATZ!).For your modem to use Use one of these commandRemote digital loopback with built-in test pattern ATS16=4 or ATS16.2=1Remote digital loopback using keyboard data ATS16=8 or ATS16.3=1
