1 dcd jumper, Dcd jumper – CANOGA PERKINS 2240 Fiber Optic Modem User Manual
Page 43
Chapter 4 Data Interfaces
RS-423/232D Model 432
43
Data Set Ready (DSR) and Test Mode (TM) are local status leads and follow the functions
described in RS-232D. DSR typically indicates that the modem is ready to handle transmit data.
During loopbacks, the behavior of this signal is dependent on the position of the DSR jumper
(see description of DSR jumper). TM indicates that a loopback is active on one or both modems.
Local Loopback (LL) and Remote Loopback (RL) are loopback control leads and perform the
same functions as the 2240 front panel LOOP switch LOC and REM positions. LL and RL are
interface signal inputs which can be used to activate the LOC or REM loop functions.
RTS_BIAS Jumper
The RTS_BIAS jumper controls the state that RTS floats to when there is no signal driving the
RTS pin. The OFF position forces this signal to the OFF (negated) state when the interface cable
is disconnected. The ON position forces it to the ON (asserted) state.
Factory setting: OFF
4.2.1 DCD Jumper
The DCD Jumper determines the source of the DCD output. In the CTRL position, the DCE
output functions as the output for the RTS input at the far end. In the CD jumper position and with
local RTS ON, CTS will turn ON either when the modem's fiber optic receiver is in sync (main
PCBA internal switch S1 CD/DCD = OFF and CD/SYNC = ON) or the state of the RTS signal at
6
DSR
DCE Ready
from modem
7
SG
Signal Ground
-
8
DCD
Receive Line Sig. Det.
from modem
12
SDCD
Secondary Line Sig. Det.
from modem
13
SCTS
Secondary CTS
from modem
14
STD
Secondary TD
to modem
15
SCT
Transmit Clock
from modem
16
SRD
Secondary RD
from modem
17
SCR
Receive Clock
from modem
18
LL
Local Loopback
to modem
19
SRTS
Secondary RTS
to modem
20
DTR
DTE Ready
to modem
21
RL
Remote Loopback
to modem
22
RI
Ring Indicator
from modem
23
DSRS
Data Signal Rate Selector to modem
24
SCTE
Transmit Clock External
to modem
25
TM
Test Mode
from modem
Table 4-2. RS-232D Pinouts (Continued)
Pin
Number
RS-232D
Pin Name
(abbrev)
Full Name
Direction