telecom@ucbvax.ARPA (05/04/85)
From: Jon Solomon (the Moderator) <Telecom-Request@BBNCCA> TELECOM Digest Fri, 3 May 85 23:36:26 EDT Volume 4 : Issue 187 Today's Topics: Racal-Vadic Modem Query Re: TELECOM Digest V4 #186 Telephone wiring diagram? Re: TELECOM Digest V4 #185 ---------------------------------------------------------------------- To: TELECOM@bbncca.ARPA Subject: Racal-Vadic Modem Query Date: 01 May 85 23:11:58 PDT (Wed) From: larus%ucbdali@Berkeley I have a Racal-Vadic VA3451 Auto Dial Modem at home. When I dial into Berkeley's computers, about half the time I get a "CONNECTED" message and then nothing. No manner of key pounding will get me a login prompt. However, hanging up and trying again usually works. I am begining to suspect that there is some sort of of incompatability between R-V's triple protocol and the 201/212 modems on the computers. Has anyone else seen this problem and know of a solution. Thanks, /Jim ------------------------------ From: ihnp4!ihopa!riccb!jmc@Berkeley Date: 2 May 85 04:43:21 CDT (Thu) To: ihopa!ihnp4!ucbvax!telecom@Berkeley Subject: Re: TELECOM Digest V4 #186 Regarding surge protecters for telephone lines. Surge protectors, as the name implies, protect the equipment and user on a telephone line from large voltage transients. Normal telephone equipment is transformer coupled to the line and if they meet REA spec's should be able to handle 1000 V transients without burning. To limit lightening strikes Bell puts arrestors on the office end which limit transients to about 400 V. I believe arrestors are also used on the customer premises but I'm not sure what the limits are. $19 seems outrageous since these things are nothing but gas discharge tubes. I've seen them go down to 90 V, anything below that will start firing on ringing voltage. REA standards say the equipment won't burn after so many consecutive 1000 V strikes but does not imply that it must work afterwards. Jeff McQuinn * Rockwell International ------------------------------ Date: Wed 1 May 85 20:01:31-PDT From: Doug <Faunt%hplabs.csnet@csnet-relay.arpa> Subject: Telephone wiring diagram? To: telecom@bbncca.ARPA I have a old Trimline telephone that I'd like to get wired correctly. It is a '69 vintage unit that requires a transformer for lighting the buttons. I've managed to get the switch-hook wiring sort-of figured out, but can't seem to get the bell to work properly. The bell has five wires coming out of the bell, colored: Red, Black, Blue, Slate, Slate/Red The terminal plate has a capacitor between terminals K and A. The rest of the terminals are marked L1, L2, 1, 3, 4, B, F, G, and C The handset has 5 leads: Red and Green are Tip and Ring, Black and White are the lighting circuit, and Yellow is ? Does anyone have a wiring diagram? faunt%hplabs@CSNET-RELAY.ARPA ------- ------------------------------ Date: Wed, 1-May-85 22:20:26 PDT From: vortex!dave@rand-unix (David H. Siegel) Subject: Re: TELECOM Digest V4 #185 To: randvax!telecom-request@bbncca Cc: vortex!i@rand-unix Lightning is a wonderful display of nature. It is so wonderful that you do not have to be anywhere near it to lose eyour electronic toys. 1. Underground telco cables are not immune to hits. Surges are induced very well in burried cabl. 2. Protectors only divert "excess" voltages to ground... when they get around to it. The idea is to keep the amount of energy to the inside telset as low as possible. 3. MOV's can only handle their rated power dissipations before they self- distruct. In sensibly designed equipment they are only used as secondary protection. (The protectors are the primary line of defense). 4. The best protection is obtained with a combination of devices: Gas tube protectors, premises equipment with good secondary protection to a good earth ground and well grounded chassis. For power a 3 mode surge arrester is a good start (well grounded please). For CATV drops grounding blocks are a must. A cheap 50 cent balun transformer on the back of your TV can't hurt either. 5. No kite flying during thunderstorms, or your Telcom Digest will be cancelled. Dave Siegel ------------------------------ End of TELECOM Digest ******************************