Motorola 3260FAST User Manual page 172

Table B-1.
Modem/Computer Interface Connections (Continued)
EIA/TIA
Pin 232-D ITU V.24
12 CI 112
13 — 110
14 — —
15 DB 114
16 — 117
17 DD 115
18 — 141
19 — —
20 CD 108.1/
108.2
21 — 140
22 CE 125
23 CH/CI 111/112
24 DA 113
25 — 142
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Signal Definition
Data Signal Rate CI (112) is passed from modem to terminal, indicating signaling rate.
Indicator When signal is on, modem operates at 2400 bps or greater. When
signal is off, modem operates below 2400 bps.
Signal Quality Signal passes from modem to terminal indicating signal quality of
telephone line. When signal is on, signal quality is acceptable. When
signal is off, signal quality is poor.
Ext Select (All models.) Signal passed from terminal to modem to select between
two option sets. Works in conjunction with Ext Select option.
(Models 3261/3263/3266/3268 only.) Signal passed from terminal to
modem indicating whether to use a dial line or a leased line. When
signal is on, modem uses a dial line. When signal is off, modem uses a
leased line. This signal is used in Restoral mode only.
Transmitter Local modem sends an internally generated transmit timing signal to
Signal Element local terminal to synchronize transmitted data (TXD). See
Timing Clock=Internal.
Standby Indicator (Models 3261/3263/3266/3268 only.) Signal passed from modem to
terminal indicating type of line in use. When signal is on, modem is on
a dial line. When signal is off, modem is on a leased line. This signal is
used in Restoral mode only.
Receive Signal Timing signal extracted from the received carrier. Local modem
Element Timing transmits this signal to the DTE to synchronize received data (RXD).
Local Analog Initiated at local terminal and passed to local modem, causing it to
Loopback Test initiate local analog loopback test.
— Not used.
Data Terminal 108.1—Sent by DTE; causes the modem to connect to the phone line.
Ready (DTR)
108.2—Sent by DTE; allows the modem to connect to the phone line.
Remote Digital Signal initiated at local terminal and passed to local modem, causing it
Loopback Test to initiate remote digital loopback test (V.54 Loop 2).
Ring Indicator Passed from local modem to local terminal. On during ringing, off
(RI) between rings and when no ring received.
Data Signal Rate CI passed from modem to terminal indicating signaling rate. CI is set
Select/Indicator high for data rates greater than 2400 bps; otherwise, it is set low. CI is
also set low while the modem is disconnected. The function of this pin
is determined by the setting of rear panel Switch 1. CH (input) signal
has no effect on modem operation.
External Signal Transmit timing signal generated by some synchronous DTEs,
Element Timing providing clock to the local modem. See Clock=External setting.
Test Indicate (TI) Local modem signals to local terminal when local modem is in test.
The terminal can initiate a Busy Out condition on this circuit. The
status of this signal is determined by the status of rear panel Switch 2
and front panel option DTE Pin 25 configured for Test or Busy.
Cabling and Interface Pinouts B-3