smb@ulysses.UUCP (Steven Bellovin) (03/14/85)
What is the maximum distance (according to the spec) between a V.35 device
and the modem? How far can I stretch that in reality? Specifically, I have
a DEC DMR-11 and an AT&T CSU (channel service unit) for 56Kb DDS service,
and the machine I want to plug the DMR into isn't conveniently close to
the modem rack.
Reply by mail, please.
--Steve Bellovin
{ihnp4,ucbvax,most of BTL,unc}!ulysses!smb
ulysses!smb@berkeley.arpa
smb.ulysses@btl.csnet
201-582-5886phil@amdcad.UUCP (Phil Ngai) (08/16/86)
Recently someone asked about V.35. In general, V.35 control signals
look like RS-232 and the clock and data signals are what you would
expect (transmit, receive, and three clock lines) except they are
differentially driven and use two wires each.
The control signals are especially like RS-232 in that few vendors
implement the same set. However, this has not been a problem for us.
We had been buying 34 conductor V.35 cables which were huge and
difficult to handle. I decided to try to get smaller cables. It turns
out that we can get by with 18 conductors. I constructed a table to
help me decide which conductors to provide. Perhaps someone else will
find it useful. Additions to the table are welcomed.
Black Box M/34 switch.
A,B,C,D,E,F, P,R,S,T,U,V,W,X,Y,AA
No H,J,K. DTR, RI, LT.
HP BERT tester.
B,C,D,E,F,H, P,R,S,T,U,V,W,X,Y,AA
No A,J,K. FG, RI, LT.
AMD Cable.
B,C,D,E,F,H,J,K,P,R,S,T,U,V,W,X,Y,AA
No A. FG.
BRIDGE GS/3.
A,B,C,D, F, P,R,S,T, V, X,Y,AA
No E,H,J,K,U,W. DSR,DTR,RI,LT,SCTE
ATT 2556 DSU.
B,C,D,E,F, P,R,S,T,U,V,W,X,Y,AA
No A,H,J,K. FG, DTR, RI, LT.
--
Rain follows the plow.
Phil Ngai +1 408 749 5720
UUCP: {ucbvax,decwrl,ihnp4,allegra}!amdcad!phil
ARPA: amdcad!phil@decwrl.dec.com