What are COT's and DID's?!!?

[hav0k99]

Are they each for inbound and outbound calling?

 

[coniglio]

COTs are Central Office Trunks and I think they can always be used for in and outbound traffic. DIDs are Direct Inward Dial #s that come on a T1 that can be configured for inbound and outbound dialing. I think...

 

[acewarlock]

Both Correct

 

[senk1s]

to add to coniglio's answer

CO trunks can also be 'ordered' from the CO as incoming only, outgoing only or bothway - depnds on the CO though

 

[PEMpal]

DIDs don't have to be on T1. They can also be on analog trunks, just like COT. From the Telco you can obtain DID numbers in blocks of 20 or 100, to go along with a couple of DID trunks. For example, I have two blocks of 100 DID numbers that terminate on six DID trunks. When an outsider dials one of my DIDs, it comes in on one of the six trunks. When all six trunks are busy (ATB), the next incoming DID call gets a busy signal. By watching my PBX traffic reports, I can see that I have not had a single case of ATB in the past four years, since I went from 3 DID trunks to 6.

 

[hav0k99]

So what is the difference if they can both be used for inbound and outbound dialing? One's on copper and one's on T1 fiber?

 

[hawks]

In the old days......DID was for inbound only as far as I know. But with todays switches and software they can do two way calling on them.

 

[johnpoole]

the main difference is cot's come in to your switch with no predertimed target. if in the route auto =yes then the trunk will have a atdn prompt, for attendant dn.. a did via prior agreement send digits (3,4,5 or 7) so of i have 6 did trunks and and paying for 100 did numbers, agree with the provider that i need 4 digits, a caller dials xxx 1000, if i have a ext 1000, that call is direct in dial to that ext. with 100 in my group, all ext between 1000 and 1099, are did. with 6 did trunks i can receive 6 calls at a time. not a very fat setup, for 100 users i would 10 or 12 trunks. that switch would be "graded" 1 to 10. the office your home phone works out of is normal 4 to 10.. 40 percent of the stations can be in use at any one time.. my 81 has 10,000 did's with 240 two way trunks. almost never hit a busy.. with did being in and out, we do not need cot's anymore. our ld trunks are in reality did's, 80+ two way did, we accept 4 digit dnis (did's for ld) for 800 inbound. ..

did and cot can be two way. did's send digits, cots just ring in. other start and signal arangements or more common for cot's then the ring we got at home. ground start, wink start, imm start, etc... hope this helps, most of us have done this so long that we sometimes don't realize that we talk in strange ways

john poole
bellsouth business
columbia,sc