26
Canoga Perkins
3.4 RS-530 Interface Model -R30
The EIA RS-530 interface uses RS-422 (balanced) electrical signals for all interface circuits (data,
clock and control), except for the loopback (local/remote), and test mode pins which use RS-423
(unbalanced bipolar) electrical signals. The DB-25 pin assignments and signals supported are
detailed in Table 3-D
.
Jumper options are detailed in Table 3-E.
Normally, the control leads RTS, CTS, DSR and TM are supported locally (i.e., no end-to-end
connectivity). RTS can be used to control DCD at the far-end if the 2270 is set for flow control.
NOTE: DTR to RI is not supported on the 2270.
A 3.5 mm stereo phone jack is provided for an alarm contact output for 2270 applications. This
contact is controlled by the presence of CD (Optical Receive Carrier Detect). If CD is not valid or
power is lost, the relay is in the alarm state. A jumper (RLY) controls the selection of either the
open or closed state. This is a three-contact jack. The alarm circuit is present between the tip and
sleeve contacts. The contact rating is 24VAC or 24VDC at 0.5A.
Table 3-D. RS-530 Signals and Pin Assignments
Pin #
Signal Name
Direction
FG
01
Frame Ground
-
TD
02/14
Transmit Data
to modem
RD
03/16
Receive Data
from modem
RTS
04/19
Request to Send
to modem
CTS
05/13
Clear to Send
from modem
DSR
06/22
Data Set Ready
from modem
SG
07
Signal Ground
-
DCD
08/10
Data Carrier Detect
from modem
SCR
17/09
Receive Clock
from modem
SCT
15/12
Transmit Clock
from modem
SCTE 24/11
External Tx Clock
to modem
DTR
20/23
Data Terminal Ready
to modem
LL
18*
Local Loopback
Loopback
RL
21*
Remote Loopback
Loopback
TM
25
Test Mode
from modem
* These signals are single ended and activate a modems system
test. All other signals are balanced.