There were some questions about serial I/O maximum cable runs. Here's the
poop from the specs for RS232, RS422, RS423, and RS485. A good source
of single powersupply conversion chips is Maxim.
We sure need somebody to come up with a TSR that will interface
CT with an ethernet.
Summary of RS-232C, RS-423, RS-422 and RS-485 Standards
Specification RS-232-C RS-423 RS-422 RS-485
------------------------------------------------------------------------
Receiver input +-3 to +-200mV to +-200mV to +_200Mv to
voltage +-15V +-12V +-7V +-7V to +-12V
------------------------------------------------------------------------
Driver output +-5 to +-3.6V to +-2V to +-1.5V to
signal +-15V +-6V +-5V +-5 V
------------------------------------------------------------------------
Maximum data
rate 20 Kb/s 100 Kb/s 10 Mb/s 10 Mb/s
------------------------------------------------------------------------
Maximum cable
length 50 feet 4000 feet 4000 feet 4000 feet
------------------------------------------------------------------------
Driver source
impedance 3 K to 7 K 450 min 100 54
------------------------------------------------------------------------
Receiver input
resistance 3 K 4 K minimum 4 K minimum 12 K minimum
------------------------------------------------------------------------
Mode Single-ended Single-ended Differential Differential
------------------------------------------------------------------------
Number of
drivers and
receivers
allowed on one
line 1Dr/1Rx 1Dr/10Rx 1 Dr/10Rx 32Dr/32Rx
------------------------------------------------------------------------
--
Submissions: ct-user@eng.pko.dec.com
Administrative requests: ct-user-request@eng.pko.dec.com
Problems: reisert@eng.pko.dec.com
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