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Unstructured Frame for E1

We have a branch office in Mexico, and headquarter in USA. We recently purchased (2) 2621-XM routers with VWIC-2MFT-T1-DI for USA and VWIC-2MFT-E1-DI for Mexico location.

This will be an standard TDM configuration where I configured 8 channels for voice, and 16 for data. However, I couldn't bring the circuit up for Mexico. Finally , I decided to call Telnor (

Telco for Mexico, and they are giving me a lame excuse that your E1 card doesn't support Unstructured Frame, and that is why it wouldn't work. Below is my configs.

See the attached configs, and please advise


Re: Unstructured Frame for E1

The most common form of E1 signalling in Mexico is E1R2 whgich uses MF tones, while the US would probably be E&M wink using DTMF tones.

T1 CAS uses timeslots 6,12, 18 and 24 to pass the ABCD bits via robbed bit signalling. E1 CAS uses timeslot 16 to pass the ABCD bits.

E&M uses the state of idle and sieze, while E1R2 uses the states seize, seize ack, answer, clear bwd, clear fwd and idle.

There is no way for the D&I function to firstly convert between the robbed bits of the T1 to the single dedicated channel of the E1. Secondly the call states and bit patterns are different between E&M and E1R2.

There is no way this is going to work with Drop and Insert... The only way to do this is to put voice cards and DSP's at each site and interpret the signalling locally and switch the calls as VOIP across the data link.

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