Nortel Networks 553-3001-211 manual Inbound Hotline modem pooling, Call disconnection

NT7D16 Data Access card Page 451 of 894

Table 153

Connect and disconnect protocol (Part 3 of 12)

Mode of
operation	Interface application	Comments
Mode 1	Inbound Hotline modem	Inbound Hotline modem pooling:
	pools
	Most dumb modems can be	Modem sends ring/no ring cycle (2 seconds ON, 4
	used for this application.	seconds OFF) to initiate connection.
		DAC responds by trying to establish a Hotline call
		to a specific Data Module (Autodial).
		When Data Module answers, then and only then,
		the DAC turns DTR ON.
		Modem should answer the incoming call when
		DTR goes ON and should turn DCD ON within 35
		seconds; otherwise the DAC disconnects the call.
		Call disconnection:
		Disconnection is the same as mode 0.
Mode 2	Inbound and Outbound	Inbound and Outbound modem pooling:
	modem pools (with forced	The DAC operation is identical to mode 0 except
	DTR)
		that DTR is always forced ON (except during
	Use this mode with Hayes	disconnect).
	1200 modem.
		Call disconnection:
		Disconnection is identical to mode 0 except:
		—When a call is released, the DAC turns DTR
		OFF for 0.2 second and then ON. DTR stays ON
		until the next call release.
		—The DAC ignores RI and DCD for about 2
		seconds after releasing a call. This avoids
		problems with the Hayes 1200 modem.

Circuit Card Description and Installation