16
ASYNC SHORT-HAUL MODEM MP
5.2.2 R
EMOTE
A
NALOG
L
OOP
The second test mode is Remote Analog Loop. It causes any characters sent from
the remote Modem to the local Modem to be returned to the remote device (see
Figure 5-1).
Start the test by pressing the Test button on one of the Modems. Then send data
from the other Modem (which must be in normal operating mode). If the data is
echoed back to the Modem in normal mode (for example, if characters you type
appear on your screen), the link to the Modem in loopback mode is working.
NOTE
Only the one Modem should be in test mode. The other Modem should
be in “normal” operating mode or the test will not work.
If no characters are echoed back, check the wiring between the two Modems. Wire
the Modems according to the instructions in
Chapter 4
.
Figure 5-1. Loopback Test Modes.
RD
TD
TD
RD
Local 1060
In Normal Mode
Remote 1060
In Normal Mode
TX+
TX-
RX-
RX+
RX+
RX-
TX-
TX+
RD
TD
TD
RD
Local 1060
In Loopback Mode
Remote 1060
In Normal Mode
RX+
RX-
TX-
TX+
TX+
TX-
RX-
RX+
Local Modem
In Normal Mode
Remote Modem
In Normal Mode
Local Modem
In Loopback Mode
Remote Modem
In Normal Mode
