[comp.sys.ibm.pc.hardware] Zenith 150 Serial Port Help

harvey@oasys.dt.navy.mil (Betty Harvey) (05/22/91)

I am installing an external high speed modem on a Zenith 150 (non-Tempest).  
This is someone else machine and I can't find any documentation.  This
machine has been passed through three or four users and the documentation
has been lost through the transitions.  I have a Tempest Zenith 150
manual but the jumpers are different.

An internal external Hayes 1200 baud modem has been installed and uses
COM1.  The original serial port is not COM2.  Everything on COM2 works
well except no video comes back to the screen.  I can watch the lights
on the modem and see every command I type being executed.  Really
strange.

My question:  Does anyone know which switches or jumpers I should reset
on the board to reset the COM port to COM1 so I can take the interal
Hayes modem out, or does anyone have any theories why I can't get
video back from the modem? 

/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
Betty Harvey  <harvey@oasys.dt.navy.mil>   | 
David Taylor Research Center               |
Office Automation Systems Branch           |
Bethesda, Md.  20084-5000                  |
                                           |
(301)227-4901                              |
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nef@mace.cc.purdue.edu (paulhicks) (05/23/91)

In article <7907@oasys.dt.navy.mil> harvey@oasys.dt.navy.mil (Betty Harvey) writes:
>My question:  Does anyone know which switches or jumpers I should reset
>on the board to reset the COM port to COM1 so I can take the interal
>Hayes modem out, or does anyone have any theories why I can't get
>video back from the modem? 
>
I am looking at the manual right now for the Zenith Z-100 series.
On the Video board, there is a switch(SW301)with two settings,IRQ4+IRQ3,
it is located toward the bottom of the board, away from the 
bus.  The manual says for switch SW301
SWITCH 
SECTION POSITION	FUNCTION

2    	ON	SERIAL PORT IS ADDRESSED AS COM1 (IRQ4)
	OFF	SERIAL PORT IS ADDRESSED AS COM2 (IRQ3)

As ussual, I accept no responsibility for your actions
Although I do hope that this info helps!

Good luck, Paul