Line state of RS232 and RS485 chips while shutdown?

In article , Nicholas Karsen writes

Which RS485 driver? If using the SN75176 or similar, it will not like having RS232 voltages on its RS485 line pins. Its absolute max voltages are +12V, -5V which may be exceeded by RS232.

Is there a bidirectional multiplexer which could isolate these two line drivers with maximum and minimum voltages of +-20 volts, minimal propagation delay, and low impedence, other than a mechanical switch. I have been searching, however most silicon based multiplexers are limited to the voltages ranges of their device families.

Thanks, Nicholas

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There are a lot of products on the market that do exactly this, so there must be RS-485 drivers for which RS-232 levels are not out of bounds.

Grant Edwards wrote in news: snipped-for-privacy@isis.visi.com:

Maxim Max3160?

Linear Tech and Sipex also both make these parts, RS-232, RS-422, RS-485. I have one on our DSP boards. But they are pricy. Around $6 each for LT1334 with 4/4 single ended and 2/2 differential drivers/receivers.