17
CHAPTER 4: Operation
4.3.3 C
ONNECTING
T
HREE
A
SYNCHRONOUS
L
INES TO
O
NE
M
ULTIPLEXOR
C
HANNEL
As described in
Section 4.1.3
, three separate asynchronous data-only channels
(no control signals) can be transmitted through one channel of the
multiplexor. To connect three standard RS-232 cables to one multiplexor
channel requires an adapter cable (product code EYN355). This cable has
female connectors labeled A, B, and C, and is wired according to Table 4-2
below.
If any of the three terminal devices on a given channel require the Data Set
Ready, Clear to Send, or Data Carrier Detect signals, these can be provided in
the following ways:
• Data Set Ready: Pin 6 of the 3-to-1 adapter cable’s female connector(s)
must be wired to Pin 6 of the cable’s male connector.
• Data Carrier Detect: Pin 8 of the adapter cable’s female connector(s)
must be wired to Pin 8 of the cable’s male connector.
(Neither of the above arrangements is standard with the normal adapter cable
EYN355, but we will be happy to customize the cable for you. Call us for a
quote.)
• Clear to Send: On the adapter cable, jumper together Pins 4 and 5
of the female connector corresponding to the desired device.
Table 4-2. Adapter-Cable Pinning
Male Connector
Female Connector(s)
Pin Number:
Pin Number(s):
1 ---------------------------------------------------------------- A-1, B-1, C-1
2 ---------------------------------------------------------------- A-2
3 ---------------------------------------------------------------- A-3
5 ---------------------------------------------------------------- C-3
7 ---------------------------------------------------------------- A-7, B-7, C-7
14 -------------------------------------------------------------- B-2
17 -------------------------------------------------------------- B-3
20 -------------------------------------------------------------- C-2
