Multi-Tech Systems ISIHP-4U, ISIHP-4SD manual En Flow Control, Values n = 3-7, 12

Terminal Adapter AT Commands & S-Registers

Controls how the TA responds to the DTR (Data Terminal Ready) signal. A high DTR signal tells the TA that the connected computer is ready to communicate.

&D0 TA ignores the DTR signal.

&D1 If DTR lowers when the TA is online, TA hangs up, returns to command mode, and disables autoanswer. If the TA is offline, it doesn’t answer or dial while DTR is low.

&D3 When DTR lowers, the TA resets the data port and disables autoanswer. If DTR lowers when the TA is online, the TA hangs up, resets the active configuration to the stored configuration, and disables autoanswer.

&D4 &D4 will ignore DTR only when answering a data call. If DTR is low when an incoming data call is present, the TA will answer the call. If DTR goes high during that call, nothing will happen. However, if DTR goes high and then drops for the minimum time specified by S25, then the call will be disconnected just as it would with &D1. &D4 is the same as &D1, except that &D4 can answer a data call without DTR and DTR can remain low for the duration of the call. But if DTR goes high, then &D4 will behave like &D1.

Note: If you want to accept calls while DTR is low, the TA must be config- ured to ignore DTR. This is accomplished by entering AT&D0<cr>. With this configuration, the TA is able to accept calls while DTR is low. If this configuration setting is not made, the TA rejects incoming calls until DTR is high while the calls comes in.

&En Flow Control

Values: n = 3–7, 12, 13

Default: &E4, &E6, &E13

118 MultiModemISI Hybrid Series, ISIHP-2S/2U/4S/4U/4SD